Merge pull request #1 from prashantsinalkar/masterHEADmaster

Initial commit

11 files changed, 3366 insertions, 0 deletions

diff --git a/Engineering_Physics_by_A_Marikani/1-Ultrasonics.ipynb b/Engineering_Physics_by_A_Marikani/1-Ultrasonics.ipynb
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+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 1: Ultrasonics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.1: Fundamental_frequency_of_vibration.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"// Example No.1.1.\n",
+"// Page No.28.\n",
+"clc;clear;\n",
+"t = 0.15*10^(-2);//Thickness of the quartz crystal -[m].\n",
+"Y = 7.9* 10^(10);//Young's modulus of quartz -[N/m^2].\n",
+"d = 2650;//Density of quartz -[kg/m^3].\n",
+"f = (1/(2*t))*(sqrt(Y/d));//'f' is fndamental frequency of vibration.\n",
+"f = f*10^(-6);//fundamental frequency of vibration.\n",
+"printf('\nThe fundamental frequency of vibration of the crystal is %.4f MHz',f);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.2: Fundamental_frequency_and_first_overtone.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"// Example No.1.2.\n",
+"// Page No. 28.\n",
+"clc;clear;\n",
+"t = 1*10^(-3);//Thickness of the quartz crystal -[m].\n",
+"Y = 7.9* 10^(10);//Young's modulus of quartz -[N/m^2].\n",
+"d = 2650;//Density of quartz -[kg/m^3].\n",
+"p = 1;\n",
+"f1 = (p/(2*t))*(sqroot(Y/d));//For fundamental frequency  p=1.\n",
+"printf('\nThe fundamental frequency of vibration of the crystal is %3.3e Hz',f1);\n",
+"p = 2;\n",
+"f2 = (p/(2*t))*(sqroot(Y/d));// f2 is frequency of first overtone and for the first overtone P=2.\n",
+"printf('\nThe frequency of the first overtone of the crystal is %3.3e Hz',f2);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.3: Velocity_of_ultrasonic_wave.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"// Example No.1.3.\n",
+"// Page No.29.\n",
+"clc;clear;\n",
+"w = 5.893*10^(-7);//Wavelength of the light -[m].\n",
+"f = 1*10^(8);//Frequency of the ultrasonic transducer -[Hz].\n",
+"n = 1;//Order of diffraction.\n",
+"d = 7.505*10^(-6);\n",
+"w = 2*d;//wavelength of the ultrasonic wave.\n",
+"printf('\nThe wavelength of the ultrasonic wave is %3.3e m',w);\n",
+"v = f*w;//Velocity of the ultrasonic wave.\n",
+"printf('\nThe velocity of ultrasonic wave is %.f m/s',v);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.4: Doppler_shifted_frequency.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.1.4.\n",
+"// Page No.29.\n",
+"clc;clear;\n",
+"f = 2*10^(6);//frequency of transducer -[Hz].\n",
+"cosq = cosd(30);//Angle of inclination of the probe -[degree].\n",
+"c = 800;//Velocity of ultrasonic wave -[m/s].\n",
+"v = 3;//Speed of blood -[m/s].\n",
+"delf = ((2*f*v*cosq)/c);//Doppler shifted frequency.\n",
+"printf('\nThe Doppler shifted frequency is %3.3e Hz',delf);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 1.5: Velocity_of_ultrasonic_waves.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.1.5.\n",
+"// Page No.30.\n",
+"clc;clear;\n",
+"Y = 7.9*10^(10);//Young's modulus of quartz -[N/m^2].\n",
+"d = 2650;//Density of quartz -[kg/m^3].\n",
+"v = sqroot(Y/d);//Velocity of ultrasonic wave.\n",
+"printf('\nThe velocity of the ultrasonic waves is %.2f m/s',v);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/10-Magnetic_materials.ipynb b/Engineering_Physics_by_A_Marikani/10-Magnetic_materials.ipynb
new file mode 100644
index 0000000..b9f1c73
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+++ b/Engineering_Physics_by_A_Marikani/10-Magnetic_materials.ipynb
@@ -0,0 +1,210 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 10: Magnetic materials"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.1: Magnetization_and_flux_density.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.10.1\n",
+"//Page No.305\n",
+"//To find magnetization & flux density.\n",
+"clc;clear;\n",
+"H = (10^6);//Magnetic field strength -[A/m].\n",
+"x = (0.5*10^-5);//Magnetic suceptibility.\n",
+"M = (x*H);//Magnetization.\n",
+"printf('\nMagnetization of the material is %.0f A/m',M);\n",
+"u0 = (4*%pi*10^-7);\n",
+"B = (u0*(M+H));//Flux density.\n",
+"printf('\nFlux density of the material is %.3f Wb/m^2',B);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.2: Magnetic_moment_of_nickel_atom.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example NO.10.2\n",
+"//Page No.306\n",
+"clc;clear;\n",
+"B = 0.65;//Saturation magnetic induction -[Wb/m^2].\n",
+"p = 8906;//Density -[kg/m^3].\n",
+"Mat = 58.7;//Atomic weight of Ni\n",
+"A = (6.022*10^26);//Avagadro's constant.\n",
+"N = ((p*A)/Mat);//Number of atoms per m^-3.\n",
+"printf('\nNumber of atoms per m^-3 are %3.3e m^-3',N);\n",
+"u0 = (4*%pi*10^-7);\n",
+"um = (B/(N*u0));\n",
+"printf('\nMagnetic moment is %3.3e ',um);\n",
+"Mni = (um/(9.27*10^-24));\n",
+"printf('\nMagnetic moment of nickel atom is %.2f uB',Mni);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.3: Relative_permiability.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.10.3\n",
+"//Page No.306\n",
+"clc;clear;\n",
+"H = 1800;//Magnetic field -[A/m].\n",
+"F = (3*10^-5);//Magnetic flux -[Wb].\n",
+"A = 0.2*10^-4;//Area of cross section -[m].\n",
+"u0 = (4*%pi*10^-7);\n",
+"B = (F/A);//Magnetic flux density.\n",
+"printf('\nMagnetic flux density is %.1f Wb/m^2',B);\n",
+"ur = (B/(u0*H));//Relative permeability.\n",
+"printf('\nRelative permeability of the material is %.2f',ur);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.4: Saturation_magnetization.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.10.4\n",
+"//Page No.307\n",
+"clc;clear;\n",
+"u = 18.4;//Magnetic moment -[uB].\n",
+"uB = (9.27*10^-24);\n",
+"a = (0.835*10^-9);//Lattice parameter-[m].\n",
+"M = (u*uB/a^3);//Magnetization.\n",
+"printf('\nSaturation magnetization for Ni ferrite is %3.3e A/m',M);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.5: Magnetization_and_magnetic_flux_density.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.10.5\n",
+"//Page No.307\n",
+"clc;clear;\n",
+"H = (2*10^5);//Magnetic field strength -[A/m].\n",
+"ur = 1.01;//Relative permeability.\n",
+"u0 = (4*%pi*10^-7);\n",
+"B = (u0*ur*H);//Magnetic flux density.\n",
+"printf('\nMagnetic flux density is %.4f Wb/m^2',B);\n",
+"M = ((0.2538/u0)-(H));//Magnetization\n",
+"printf('\nMagnetization of the material is %.2f A/m',M);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.6: Succeptibility_and_magnetic_flux.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.10.6\n",
+"//Page No.307\n",
+"clc;clear;\n",
+"H = (500);//Magnetic field strength -[A/m].\n",
+"x = (1.2);//Suceptibility.\n",
+"M = (x*H);//Magnetization.\n",
+"printf('\nMagnetization of the material is %.0f A/m',M);\n",
+"u0 = (4*%pi*10^-7);\n",
+"B = (u0*(M+H));//Magnetic flux density.\n",
+"printf('\nMagnetic flux density inside the material is %3.3e Wb/m^2',B);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/11-Dielectric_materials.ipynb b/Engineering_Physics_by_A_Marikani/11-Dielectric_materials.ipynb
new file mode 100644
index 0000000..343c861
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/11-Dielectric_materials.ipynb
@@ -0,0 +1,229 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 11: Dielectric materials"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.1: Dielectric_constant.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.11.1\n",
+"//Page No.335\n",
+"//To find dielectric constant of the material \n",
+"clc;clear;\n",
+"C = (10^-9);//Capacitance -[F].\n",
+"d = (2*10^-3);//Distance of separation -[m].\n",
+"E0 = (8.854*10^-12);\n",
+"A = (10^-4);//Area of capacitor -[m^2]\n",
+"Er = ((C*d)/(E0*A));//Dielectric constant.\n",
+"printf('\nThe dielectric constant of the material is %.2f',Er);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.2: Electronic_polarizability.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.11.2\n",
+"//Page No.335\n",
+"//To find electronic polarizability of He gas.\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);\n",
+"Er = (1.0000684);//Dielectric constant of He-gas\n",
+"N = (2.7*10^25);//Concentration of dipoles -[per m^3].\n",
+"P = (E0*(Er-1));\n",
+"a = (P/(N));\n",
+"a = (P/(2.7*10^25));//Electronic polarizability.\n",
+"printf('\nElectronic polarizability of He gas is %3.3e F m^2',a);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.3: Polarizatio.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example NO.11.3\n",
+"//Page No.336\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);\n",
+"Er = (6);//Dielectric constant.\n",
+"E = 100;//Electric field intensity -[V/m].\n",
+"P = (E0*(Er-1)*E);//Polarization.\n",
+"printf('\nPolarization produced in a dielectric medium is %3.3e C/m^2',P);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.4: Electronic_polarizability.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example NO.11.4\n",
+"//Page No.336\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);\n",
+"R = (0.158*10^-9);//Radius of neon -[m].\n",
+"a = (4*%pi*E0*R^3);//Electronic polarizability.\n",
+"printf('\nElectronic polarizability of neon is %3.3e F m^2',a);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.5: Area_of_metal_sheet_required.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.11.5\n",
+"//Page No.336\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);// [C^2/N.m^2].\n",
+"Er = 6;//Dielectric constant.\n",
+"C = (0.02*10^-6);//Capacitance -[F].\n",
+"d = (0.002*10^-2);//Thickness of mica -[m].\n",
+"A = ((C*d)/(E0*Er));//Area of the metal sheet.\n",
+"printf('\nArea of the metal sheet required is %3.3e m^2',A);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.6: Relative_permittivity_of_the_crystal.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.11.6\n",
+"//Page No.337\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);\n",
+"P = (4.3*10^-8);//polarization -[C/m^2].\n",
+"E = 1000;//Electric field -[V/m].\n",
+"Er = ((P/(E0*E))+1);//Relative permittivity of the crystal.\n",
+"printf('\nRelative permittivity of the crystal is %.3f',Er);\n",
+"\n",
+"//Last statement of this numerical is wrong in the textbook.Here we have to find relative permittivity of the crystal and not the dielectric constant.//"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 11.7: Polarizability_of_the_material.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.11.7\n",
+"//Page No.337\n",
+"clc;clear;\n",
+"E0 = (8.854*10^-12);\n",
+"x = (4.94);//Relative suceptibility.\n",
+"N = (10^28);//Number of dipoles per unit volume [per m^3].\n",
+"a = ((E0*x)/N);//Polarizability of the material\n",
+"printf('\nPolarizability of the material is %3.3e F m^-2',a);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/12-Superconducting_materials.ipynb b/Engineering_Physics_by_A_Marikani/12-Superconducting_materials.ipynb
new file mode 100644
index 0000000..a2cfa70
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/12-Superconducting_materials.ipynb
@@ -0,0 +1,211 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 12: Superconducting materials"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.1: Critical_field.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.12.1\n",
+"//Page No.356\n",
+"//To find critical field.\n",
+"clc;clear;\n",
+"Tc = 3.7;//Critical temperature of tin -[K].\n",
+"Ho = 0.0306;//Magnetic field -[T].\n",
+"T = 2;//Temperature -[K].\n",
+"Hc = Ho*(1-((T^(2))/(Tc^(2))));//Critical magnetic field\n",
+"printf('\nCritical field at 2K is %.4f T',Hc);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.2: Critical_field.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example NO.12.2\n",
+"//Page No.356\n",
+"//To find critical field.\n",
+"clc;clear;\n",
+"Tc = 7.26;//Critical temperature of lead -[K].\n",
+"Ho = 6.4*10^3;//Magnetic field -[A/m^3].\n",
+"T = 5;//Temperature -[K].\n",
+"Hc = Ho*(1-((T^(2))/(Tc^(2))));//Critical magnetic field\n",
+"printf('\nCritical field at 5K is %.2f T',Hc);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.3: value_of_Tc.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.12.3\n",
+"//Page No.357\n",
+"//To find the value of Tc.\n",
+"clc;clear;\n",
+"M1 = (199.5^(1/2));//Atomic mass. \n",
+"M2 = (203.4^(1/2));//Atomic mass.\n",
+"Tc1 = (4.185);//Critical temperature of Hg -[K].\n",
+"Tc = (Tc1*M1/M2);//Critical temperature\n",
+"printf('\nCritical temperature of Hg with atomic mass,203.4 is %.5f K',Tc);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.4: critical_current_density.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.12.4\n",
+"//Page No.357\n",
+"//To find critical current density.\n",
+"clc;clear;\n",
+"D=1*10^(-3);//Diameter of the wire -[m].\n",
+"Tc = 7.18;//Critical temperature -[K].\n",
+"Ho = 6.5*10^4;//Critical field -[A/m].\n",
+"T = 4.2;//Temperature -[K].\n",
+"R = 0.5*10^-3;//Radius.\n",
+"I = 134.33;//Current.\n",
+"Hc = Ho*(1-((T^(2))/(Tc^(2))));\n",
+"printf('\nCritical magnetic field is %3.3e A/m',Hc);\n",
+"ic = (2*%pi*R*Hc);\n",
+"printf('\nCritical current is %.2f A',ic);\n",
+"J = (I/(%pi*R^2));\n",
+"printf('\nCritical current density is %3.3e A/m^2',J);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.5: frequency_of_radiation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.12.5\n",
+"//Page No.358\n",
+"//To find frequency.\n",
+"clc;clear;\n",
+"e = (1.6*10^-19);//value of electron.\n",
+"V = (6*10^-6);//Voltage applied across the junction -[V]\n",
+"h = (6.626*10^-34);//Planck's constant\n",
+"v = ((2*e*V)/h);//Frequency of ac signal\n",
+"printf('\nFrequency of ac signal is %3.3e Hz',v);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 12.6: Band_gap.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example NO.12.6\n",
+"//Page No.358\n",
+"//To find band gap of superconducting lead \n",
+"clc;clear;\n",
+"KB = (1.38*10^-23);//Boltzman's constant.\n",
+"Tc = (7.19);//Critical temperature of lead -[K].\n",
+"Eg = (3.5*KB*Tc);//Energy gap of semiconductor.\n",
+"printf('\nBand gap of superconducting lead is %3.3e J',Eg);\n",
+"Eg = (Eg/(1.6*10^-19*10^(-3)));\n",
+"printf('\nBand gap of superconducting lead is %.2f meV',Eg);\n",
+""
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/2-Laser.ipynb b/Engineering_Physics_by_A_Marikani/2-Laser.ipynb
new file mode 100644
index 0000000..b663583
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/2-Laser.ipynb
@@ -0,0 +1,332 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 2: Laser"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.10: angular_spread_and_divergence.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.10.\n",
+"// Page No.62.\n",
+"clc;clear;\n",
+"w = 632.8*10^(-9);//wavelength -[m]\n",
+"D = 5;//Distance -[m].\n",
+"d = 1*10^(-3);//Diameter -[m].\n",
+"deltheta = (w/d);//Angular Spread.\n",
+"printf('\nThe angular spread is %3.3e radian',deltheta);\n",
+"r = (D*(deltheta));\n",
+"r = (5*(deltheta));//Radius of the spread\n",
+"printf('\nThe radius of the spread is %3.3e m',r); //Radius of the spread.\n",
+"As = ((%pi)*r^(2));//Area of the spread\n",
+"printf('\nThe area of the spread is %3.3e m^2',As);//Area of the spread.\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.1: number_of_photons_emitted_per_second.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.1.\n",
+"// Page No.59.\n",
+"clc;clear;\n",
+"p = 5*10^(-3);// output power -[W].\n",
+"w = 632.8*10^(-9);//wavelength -[m].\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"c = (3*10^(8));//Velocity of light.\n",
+"hv = ((h*c)/(w));// Energy of one photon\n",
+"printf('\nThe energy of one photon in joules is %3.3e J', hv);\n",
+"hv = hv/(1.6*10^(-19));\n",
+"printf('\nThe energy of one photon in eV is %.2f eV',hv);\n",
+"Np = (p/(3.14*10^(-19)));//Number of photons emitted\n",
+"printf('\nThe number of photons emitted per second by He-Ne laser are %3.3e photons per second',Np);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.2: Energy_of_the_photon.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.2.\n",
+"// Page No.60.\n",
+"clc;clear;\n",
+"w = 632.8*10^(-9);//wavelength -[m].\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"c = (3*10^(8));//Velocity of light.\n",
+"E = ((h*c)/(w));// Energy of one photon\n",
+"printf('\nThe energy of emitted photon in joules is %3.3e J',E);\n",
+"E = E/(1.6*10^(-19));\n",
+"printf('\nThe energy of emitted photon in eV is %.2f eV',E);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.3: Energy_of_E3.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.3.\n",
+"// Page No.60.\n",
+"clc;clear;\n",
+"w = 1.15*10^(-6);//wavelength -[m].\n",
+"h = 6.626*10^(-34);\n",
+"c = (3*10^(8));\n",
+"hv = ((h*c)/(w));// Energy of one photon\n",
+"printf('\n The energy of emitted photon is  %3.3e J',hv);\n",
+"E = ((hv)/(1.6*10^(-19)));\n",
+"printf('\n The energy of emitted photon is  %.3f eV',E);\n",
+"E1 = 0,'eV';//Value of first energy level.\n",
+"E2 = 1.4,'eV';//Value of second energy level.\n",
+"E3 = (E2+E);//Energy value of 'E3'.\n",
+"E3 = ((1.4)+E);\n",
+"printf('\n The value of E3 energy level is %.3f eV',E3);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4: wavelength_of_the_photon.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.4;\n",
+"//Page No.60;\n",
+"clc;clear;\n",
+"E1 = 3.2;//Value of higher energy level E1 -[eV].\n",
+"E2 = 1.6;//Value of lower energy level E2 -[eV].\n",
+"E = (E1-E2);//Energy difference.\n",
+"printf('\nThe energy difference is %.1f eV', E);\n",
+"h = 6.626*10^(-34);//Planck's constant\n",
+"c = 3*10^(8);//Velocity of light.\n",
+"E = 1.6*1.6*10^(-19);\n",
+"w = ((h*c)/(E));\n",
+"printf('\nThe wavelength of the photon is %3.3e m', w);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.5: wavelength_of_the_laser.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.5.\n",
+"// Page No.60.\n",
+"clc;clear;\n",
+"E = 1.42;//Bandgap of Ga-As -[eV]\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"c = 3*10^(8);//Velocity of light.\n",
+"w = ((h*c)/(E*1.6*10^(-19)));\n",
+"printf('\nThe wavelength of the laser emitted by GaAs is %3.3e m',w);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.6: Relative_population_between.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.6.\n",
+"// Page No.61.\n",
+"clc;clear;\n",
+"T = 300;//Temperature -[K]\n",
+"K = 1.38*10^(-23);//Boltzman's constant.\n",
+"w = 500*10^(-9);//wavelength -[m].\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"c = (3*10^(8));//velocity of light.\n",
+"//By Maxwell's and Boltzman's law.\n",
+"N = exp((h*c)/(w*K*T)); //Relative population.\n",
+"printf('\nThe relative population between energy levels N1 and N2 is %3.3e',N);//(Relative population between N1 & N2)."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.7: Ratio_between_stimulated_and_spontaneous_emission.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.7.\n",
+"// Page No.61.\n",
+"clc;clear;\n",
+"T = 300;//Temperature -[K]\n",
+"K = 1.38*10^(-23);//Boltzman's constant\n",
+"w = 600*10^(-9);//wavelength-[m]\n",
+"h = 6.626*10^(-34);\n",
+"v = (3*10^(8));//velocity.\n",
+"S = (1/((exp((h*v)/(w*K*T)))-1));//Se=stimulated emission & SPe= spontaneous emission\n",
+"printf('\nThe ratio between stimulated emission and spontaneous emission is %3.3e.\nTherefore, the stimulated emission is not possible in this condition.',S);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.8: Efficiency_of_laser.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.8.\n",
+"// Page No.62.\n",
+"clc;clear;\n",
+"Op = 5*10^(-3);//Output power -[W].\n",
+"I = 10*10^(-3);//Current -[A].\n",
+"V = 3*10^(3);//Voltage -[V].\n",
+"Ip = (10*10^(-3)*3*10^(3));//Input power.\n",
+"Eff = (((Op)/(Ip))*(100));//Efficiency of the laser.\n",
+"printf('\nThe efficiency of the laser is %.6f percent',Eff);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.9: Intensity_of_the_laser.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.2.9.\n",
+"// Page No.62.\n",
+"clc;clear;\n",
+"P = 1*10^(-3);//Output power -[W].\n",
+"D = 1*10^(-6);//Diameter -[m].\n",
+"r = 0.5*10^(-6);//Radius -[m]\n",
+"I = (P/(%pi*r^(2)));// Intensity of laser.\n",
+"printf('\nThe intensity of the laser is %3.3e W/m^2',I);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/3-Fibre_optics.ipynb b/Engineering_Physics_by_A_Marikani/3-Fibre_optics.ipynb
new file mode 100644
index 0000000..f8f7a5c
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/3-Fibre_optics.ipynb
@@ -0,0 +1,207 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 3: Fibre optics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.1: Numerical_aperture_of_the_fibre.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No. 3.1.\n",
+"//Page No.98.\n",
+"//To find numerical aperture.\n",
+"clc;clear;\n",
+"n1 = 1.6;//Refractive index of core.\n",
+"n2 = 1.5;// Refractive index of cladding.\n",
+"NA = sqroot((n1^(2))-(n2^(2)));//Numerical Aperture.\n",
+"printf('\nThe numerical aperture of the fibre is %.4f',NA);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.2: Numerical_aperture_and_acceptance_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.3.2.\n",
+"// Page No.98.\n",
+"//To calculate numerical aperture and acceptance angle.\n",
+"clc;clear;\n",
+"n1 = 1.54;//Refractive index of core.\n",
+"n2 = 1.5;// Refractive index of cladding.\n",
+"no = 1;\n",
+"NA = sqroot((n1^(2))-(n2^(2)));//Numerical Aperture.\n",
+"printf('\nThe numerical aperture of the fibre is %.4f',NA);\n",
+"t = asind(NA/no);// Acceptance angle.\n",
+"printf('\nThe acceptance angle of the fibre is %.4f degree',t);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.3: critical_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.3.3.\n",
+"//Page No. 99.\n",
+"//To find critical angle.\n",
+"clc;clear;\n",
+"n1 = 1.6;//Refractive index of core.\n",
+"n2 = 1.49;// Refractive index of cladding.\n",
+"Qc = asind((n2)/(n1));//Critical angle.\n",
+"printf('\nThe critical angle of the fibre is %.2f degree',Qc);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.4: Refractive_index_and_acceptance_angle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"\n",
+"//Example No.3.4.\n",
+"//Page No. 99.\n",
+"//To find refractive index of core and acceptance angle.\n",
+"clc;clear;\n",
+"NA = 0.15;//Numerical aperture.\n",
+"n2 = 1.55;//Refractive index of cladding.\n",
+"n0 = 1.33;//Refractive index of water.\n",
+"n1 = sqroot((NA^(2))+(n2^(2)));// Refractive index of core.\n",
+"printf('\nThe refractive index of the core is %.4f',n1);\n",
+"t = asind(NA/n0);// Acceptance angle.\n",
+"mprintf('\nThe acceptance angle of the fibre is %.3f degree',t);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.5: Refractive_index_of_the_core.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.3.5.\n",
+"//Page No. 100.\n",
+"//To find refractive index of cladding.\n",
+"clc;clear;\n",
+"d = 100;//Core diameter.\n",
+"NA = 0.26;//Numerical aperture.\n",
+"n1 = 1.5;//Refractive index of core.\n",
+"n2 = sqroot((n1^(2))-(NA^(2)));// Refractive index of cladding.\n",
+"printf('\nThe refractive index of the cladding is %.3f',n2);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.6: Refractive_indices_of_core_and_cladding.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.3.6.\n",
+"// Page No.100.\n",
+"//To find refractive idex.\n",
+"clc;clear;\n",
+"NA = 0.26;//Numerical aperture.\n",
+"del = 0.015;//Refractive index difference of the fibre.\n",
+"n1 = sqroot((((NA)^(2))/(2*del)));//Refractive index of the core\n",
+"printf('\nThe refractive index of the core is %.2f',n1);\n",
+"n2 = sqroot((n1^(2))-(NA^(2)));// Refractive index of cladding.\n",
+"printf('\nThe refractive index of cladding is %.3f',n2);\n",
+""
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/4-Quantum_physics.ipynb b/Engineering_Physics_by_A_Marikani/4-Quantum_physics.ipynb
new file mode 100644
index 0000000..a73738c
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/4-Quantum_physics.ipynb
@@ -0,0 +1,535 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 4: Quantum physics"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.10: Probability_of_finding_the_practicle.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.10\n",
+"// Page No.138.\n",
+"//To find the probability.\n",
+"clc;clear;\n",
+"L = 25*10^(-10);//Width of the potential well -[m].\n",
+"delx = 0.05*10^(-10);//Interval -[m].\n",
+"x = int(1);\n",
+"P = (((2*delx)/L)*x);//'P' is the probability of finding the practicle at an interval of 0.05 .\n",
+"printf('\nThe probability of finding the particle is %.3f',P);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.11: Lowest_energy_of_the_electron.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.4.11.\n",
+"//Page No.138.\n",
+"clc;clear;\n",
+"n = 1;//For the lowest energy value n=1.\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"L = 1*10^(-10);//Width of the potential well -[m].\n",
+"m = 9.1*10^(-31);//Mass of the electron.\n",
+"E = ((n^(2)*h^(2))/(8*m*L^(2)));\n",
+"E = ((h^(2))/(8*m*L^(2)));// For the lowest energy value n=1.\n",
+"printf('\nThe lowest energy of the electron in joules is %3.3e J',E);;// Lowest energy of the electron in joules.\n",
+"E = (E/(1.6*10^(-19)));\n",
+"printf('\nThe lowest energy of the electron in eV is %.2f eV',E);// Lowest energy of the electron in eV.\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.12: Lowest_energy_of_the_electron.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.12.\n",
+"//Page No.139.\n",
+"//To find lowest energy of the electron.\n",
+"clc;clear;\n",
+"n = 1;//For the lowest energy value n=1.\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"L = 1*10^(-10);//Width of the potential well -[m].\n",
+"m = 9.1*10^(-31);//Mass of the electron.\n",
+"E = (2*(n^(2)*h^(2))/(8*m*L^(2)));\n",
+"//'E' is the Lowest energy of the system.\n",
+"printf('\nThe lowest energy of the system in joules is %3.3e J',E);\n",
+"E = (E/(1.6*10^(-19)));\n",
+"printf('\nThe lowest energy of the system in eV is %.2f eV',E);// Lowest energy of the electron in eV."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.13: Lowest_energy_of_the_system.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.13.\n",
+"//Page No.139.\n",
+"clc;clear;\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"L = 1*10^(-10);//Width of the potential well -[m].\n",
+"m = 9.1*10^(-31);//Mass of the electron.\n",
+"E = ((6*h^(2))/(8*m*L^(2)));\n",
+"printf('\n 1) The lowest energy of the system in joules is %3.3e eV',E);\n",
+"E = (E/(1.6*10^(-19)));\n",
+"printf('\n 2) The lowest energy of the system is  %.2f eV',E);\n",
+"disp('3) Quantum numbers are,');\n",
+"n = 1;\n",
+"l = 0;\n",
+"ml = 0;\n",
+"ms = 0.5;\n",
+"ms1 = -0.5;\n",
+"printf('\ni)n = %.0f',n);\n",
+"printf(' , l = %.0f',l);\n",
+"printf(' , ml = %.0f',ml);\n",
+"printf(' , ms = %.1f',ms);\n",
+"printf('\nii)n = %.0f',n);\n",
+"printf(' , l = %.0f',l);\n",
+"printf(' , ml = %.0f',ml);\n",
+"printf(' , ms1 = %.1f',ms1);\n",
+"n=2;\n",
+"printf('\niii)n = %.0f',n);\n",
+"printf(' , l = %.0f',l);\n",
+"printf(' , ml = %.0f',ml);\n",
+"printf(' , ms = %.1f',ms);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.14: mass_of_the_alpha_practical.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.14.\n",
+"//Page No.140.\n",
+"//The mass of the particle.\n",
+"clc;clear;\n",
+"E = 0.025*1.6*10^(-19);//Lowest energy.\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"L = 100*10^(-10);//Width of the well -[m].\n",
+"m = ((h^(2))/(8*E*L^(2)));\n",
+"printf('\nThe mass of the particle is %3.3e kg',m);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.15: Energy_density.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.15.\n",
+"//Page No.141.\n",
+"//To find energy density.\n",
+"clc;clear;\n",
+"T = 6000;//Temperature -[K].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"w1 = 450*10^(-9);//wavelength -[m].\n",
+"w2 = 460*10^(-9);//wavelength -[m].\n",
+"c = 3*10^(8);//Velcity of light.\n",
+"v1=(c/w1);\n",
+"printf('\nThe velocity for wavelength 450 nm is %3.3e Hz',v1);\n",
+"v2 = (c/w2);\n",
+"printf('\nThe velocity for wavelength 460 nm is %3.3e Hz',v2);\n",
+"v = ((v1+v2)/2);\n",
+"printf('\nThe average value of v is %3.3e Hz',v);\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"d = (8*%pi*h*v^(3))/(c^(3));\n",
+"dv = d*(1/(exp((h*v)/(k*T))-1));//Energy density.\n",
+"printf('\nThe energy density of the black body is %3.3e J/m^3',dv);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.1: change_in_wavelength.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No 133.\n",
+"//Page No 4.1.\n",
+"//To find change in wavelength.\n",
+"clc;clear;\n",
+"h = 6.63*10^(-34);//Planck's constant -[J-s].\n",
+"m0 = 9.1*10^(-31);//mass of electron -[kg].\n",
+"c = 3*10^(8);//Velocity of ligth -[m/s].\n",
+"cosq = cosd(135);//Angle of scattering -[degree].\n",
+"delW = (h/(m0*c))*(1-cosq);//change in wavelength.\n",
+"printf('\nThe change in wavelength is %3.3e m',delW);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.2: comptom_shift_and_w_and_energy.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.2.\n",
+"//Page No.134.\n",
+"clc;clear;\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"m0 = 9.1*10^(-31);//mass of electron.\n",
+"c = 3*10^(8);//Velocity of ligth.\n",
+"cosq = cosd(90);//Scattering angle -[degree].\n",
+"delW = (h/(m0*c))*(1-cosq);//Compton's shift\n",
+"delW = delW*10^(10);\n",
+"printf('\na)The Comptons  shift is  %.5f A',delW);\n",
+"w = 2;//Wavelength -[A]\n",
+"W = (delW+w);// Wavelength of the scattered photon.\n",
+"printf('\nb)The wavelength of the scattered photon is % 5f A',W);\n",
+"E = (h*c)*((1/(w*10^(-10)))-(1/(W*10^(-10))));//Energy of the recoiling electron in joules.\n",
+"printf('\nc)The energy of the recoiling electron in joules is %3.3e J',E);\n",
+"E = (E/(1.6*10^(-19)));//Energy of the recoiling electron in eV.\n",
+"printf('\nc)The energy of the recoiling electron in eV is %3.3e eV',E);\n",
+"sinq = sind(90);\n",
+"Q = (((h*c)/w)*sinq)/(((h*c)/w)-((h*c)/W)*cosq);\n",
+"theta = atand(Q);\n",
+"printf('\ne)The angle at which the recoiling electron appears is %.0f degree',theta); "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.3: comptom_shift_and_wavelength.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.3.\n",
+"//Page NO.135.\n",
+"clc;clear;\n",
+"h = 6.626*10^(-34);//Planck's constant.\n",
+"mo = 9.1*10^(-31);//mass of electron.\n",
+"c = 3*10^(8);//Velocity of ligth.\n",
+"w = (1*1.6*10^(-19)*10^(6));//wavelength.\n",
+"cosq = cosd(60);\n",
+"delw = ((h/(mo*c))*(1-cosq));//Compton shift\n",
+"delw = delw*10^(10);\n",
+"printf('\n1)The Comptons shift = %.3f A',delw);\n",
+"E = ((h*c)/w);//energy of the incident photon.\n",
+"W = (delw+E);//Wavelength of the scattered photon.\n",
+"W = (0.012)+(1.242);\n",
+"printf('\n3)The wavelength of the scattered photon = %.3f A',W);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.4: Number_of_photons_emitted.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No 135.\n",
+"//Page No 4.4.\n",
+"//To find number of photons.\n",
+"clc;clear;\n",
+"h = 6.63*10^(-34);//Planck's constant.\n",
+"c = 3*10^(8);//Velocity of ligth.\n",
+"w = 5893*10^(-10);//wavelength.\n",
+"Op = 60;//output power -[W].\n",
+"E  =((h*c)/w);\n",
+"printf('\nEnergy of photon in joules is %3.3e J',E);//Energy of photon in joules.\n",
+"hv = (E/(1.6*10^(-19)));//Energy of photon in eV.\n",
+"printf('\nEnergy of photon in eV is %.3f eV',hv);\n",
+"Ps = ((Op)/(E));\n",
+"Ps = ((60)/(E));// Number of photons emitted per second.\n",
+"printf('\nThe number of photons emitted per second is %3.3e photons per second',Ps);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.5: Mass_and_energy.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No 136.\n",
+"//Page No 4.5.\n",
+"//To find mass,momentum & energy of photon.\n",
+"clc;clear;\n",
+"h = 6.63*10^(-34);//Planck's constant.\n",
+"c = 3*10^(8);//Velocity of ligth.\n",
+"w = 10*10^(-10);//wavelength.\n",
+"E = ((h*c)/w);//Energy.\n",
+"printf('\n1)The energy of photon in joules is %3.3e J',E);\n",
+"E = E/(1.6*10^(-19)*10^(3));\n",
+"printf('\n2)The energy of photon in eV is %.3f Kev',E);\n",
+"p = (h/w);//Momentum.\n",
+"p = ((6.63*10^(-34))/(10*10^(-10)));\n",
+"printf('\n3)The momentum of the photon is %3.3e kg.m/s',p)\n",
+"m = (h/(w*c));\n",
+"printf('\n4)The mass of the photon is %3.3e kg',m);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.6: DeBroglie_wavelength.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No 136.\n",
+"//Page No 4.6.\n",
+"//To find de-Broglie wavelength.\n",
+"clc;clear;\n",
+"V=1.25*10^(3);//Potential difference applied -[V].\n",
+"w=((12.27)/sqroot(V));//de-Broglie wavelength of electron.\n",
+"printf('\nThe de-Broglie wavelength of electron is %.3f A',w);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.7: wavelength.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.136 .\n",
+"//Page No. 4.7.\n",
+"//To find de-Broglie wavelength.\n",
+"clc;clear;\n",
+"E = 45*1.6*10^(-19);//Energy of the electron.\n",
+"h = 6.63*10^(-34);//Planck's constant\n",
+"m = 9.1*10^(-31);//Mass of the electron.\n",
+"w = h/(sqrt(2*m*E));//de-Broglie wavelength.\n",
+"printf('\nThe de-Broglie wavelength of the photon is %3.3e m',w);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.8: De_Broglie_wavelength.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.4.8.\n",
+"//Page No.137.\n",
+"//To find de-Broglie wavelength.\n",
+"clc;clear;\n",
+"h=6.626*10^(-34);//Planck's constant.\n",
+"v=10^(7);//Velocity of the electron -[m/s].\n",
+"m=9.1*10^(-31);//Mass of the electron.\n",
+"w=(h/(m*v));//de-Broglie wavelength\n",
+"printf('\nThe de-Broglie wavelength is %3.3e m',w);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.9: Wavelength_of_alpha_practical.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No 137.\n",
+"//Page No 4.9.\n",
+"//The de-Broglie wavelength of alpha particle.\n",
+"clc;clear;\n",
+"V = 1000;//Potential difference applied -[V].\n",
+"h = (6.626*10^(-34));//Planck's constant -[J-s].\n",
+"m = (1.67*10^(-27));//Mass of a proton -[kg].\n",
+"e = (1.6*10^(-19));//charge of electron -[J].\n",
+"w = h/sqrt(2*m*e*V);//de-Broglie wavelength\n",
+"printf('\nThe de-Broglie wavelength of alpha particle = %3.3e m',w);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/6-Crystallography.ipynb b/Engineering_Physics_by_A_Marikani/6-Crystallography.ipynb
new file mode 100644
index 0000000..5a729e8
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/6-Crystallography.ipynb
@@ -0,0 +1,609 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 6: Crystallography"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.10: Ratio_of_cubic_system.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"// Example No.6.10.\n",
+"// Page No.189.\n",
+"clc;clear;\n",
+"h=1;k=0;l=0;\n",
+"d100=1/sqrt(h^2+k^2+l^2);\n",
+"disp('Interplanar spacing for d100 plane = a');\n",
+"h=1;k=1;l=0;\n",
+"d110=1/sqrt(h^2+k^2+l^2);\n",
+"disp('Interplanar spacing for d110 plane = a/1.414');\n",
+"h=1;k=1;l=1;\n",
+"d111=1/sqrt(h^2+k^2+l^2);\n",
+"disp('Interplanar spacing for d111 plane = a/1.732');\n",
+"x = sqrt(6);\n",
+"y = sqrt(3);\n",
+"z = sqrt(2);\n",
+"printf('\nx = %.3f',x);\n",
+"printf('\ny = %.3f',y);\n",
+"printf('\nz = %.3f',z);\n",
+"printf('\nd100:d110:d111 = %.3f:%.3f:%.3f',x,y,z);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.11: Ratio_of_intercepts.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.11.\n",
+"// Page No.190.\n",
+"clc;clear;\n",
+"l1 = 6*(1/2);\n",
+"l2 = 6*(1/3);\n",
+"l3 = (6*1/6);\n",
+"disp('For the plane (231) the intercepts are (a/2),(b/3),(c/1)');\n",
+"disp('Ratio of the intercepts made by (231) plane in simple cubic crystal is as follows :');\n",
+"disp('l1:l2:l3 = 3:2:6');\n",
+"\n",
+"//As there are no numerical steps and hence the display statement has been typed directly."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.12: Length_of_the_intercepts.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"// Example No.6.12.\n",
+"// Page No.190.\n",
+"//To find the lengths of the intercepts.\n",
+"clc;clear;\n",
+"a = 0.8;\n",
+"b = 1.2;\n",
+"c = 1.5;\n",
+"disp('Ratio of the intercepts are as follows : ');\n",
+"disp('I1:I2:I3 = a:b/2:c/3');\n",
+"I1 = 0.8;\n",
+"disp('0.8:I2:I3 = a:b/2:c/3');\n",
+"disp('By substituting values');\n",
+"I2=(1.2/2);\n",
+"printf('\nI2 = %.1f A',I2);\n",
+"I3=(1.5/3);\n",
+"printf('\nI3 = %.1f A',I3);\n",
+"\n",
+"\n",
+"\n",
+"//As there are no numerical steps and hence the display statement has been typed directly."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.13: Nearest_neighbour_distance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.13.\n",
+"// Page No.191.\n",
+"//To find the nearest neighbour distance.\n",
+"clc;clear;\n",
+"disp('i)Simple cubic unit cell');\n",
+"disp('The nearest neighbour distance is a');//nearest neighbour distance.\n",
+"disp('ii)Body-centered cubic unit cell');\n",
+"disp('2r = (0.866)a');\n",
+"disp('iii)Face-centered cubic unit cell');\n",
+"disp('2r = (0.7071)a');\n",
+"\n",
+"//As there are no numerical steps and hence the display statement has been typed directly."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.14: Interplanar_distance.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.14.\n",
+"//Page No.191.\n",
+"//To find interplanar distance.\n",
+"clc;clear;\n",
+"// (h,k,l) are the miller indices of the given lattice plane (212).\n",
+"h = 2;\n",
+"k = 1;\n",
+"l = 2;\n",
+"a = 2.04;//Lattice constant -[A].\n",
+"d = (a/sqrt(h^2+k^2+l^2));\n",
+"printf('\nThe interplanar distance is %.2f A',d);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.15: Number_of_atoms_per_unit_cell.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.6.15.\n",
+"//Page No.191.\n",
+"clc;clear;\n",
+"r = 1.278*10^(-10),'m';\n",
+"M = 63.54;//Atomic weight of copper.\n",
+"Na = 6.022*10^(26);\n",
+"d = 8980;//density\n",
+"a = r*sqrt(8);//Interatomic distance.\n",
+"printf('\n The interatomic distance is %3.3e m',a);\n",
+"n = ((d*a^(3)*Na)/(M));//The number of atoms per unit cell.\n",
+"printf('\n Number of atoms per Cu unit cell is %.f',n);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.16: Miller_indices_of_the_faces.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.16.\n",
+"// Page No.192.\n",
+"//To find the miller indices.\n",
+"clc;clear;\n",
+"disp('i)Ratio of the intercepts are 0.214 : 1 : 0.188');\n",
+"disp('Miller indices for the given plane is (212)');\n",
+"disp('ii)Ratio of the intercepts are 0.858 : 1 : 0.754');\n",
+"disp('Miller indices for the given plane is (121)');\n",
+"disp('iii)Ratio of the intercepts are 0.429 : infinity : 0.126');\n",
+"disp('Miller indices for the given plane is (103)');\n",
+"\n",
+"//There are no numerical computations involved in this example and hence the display statement has been typed directly."
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.17: Number_of_atoms_present.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.13.\n",
+"// Page No.191.\n",
+"//To find the number neighbour distance.\n",
+"clc;clear;\n",
+"disp('i)For (100) plane');\n",
+"disp('Number of atoms per m^2 = 1/4r^2');\n",
+"disp('i)For (110) plane');\n",
+"c1 = 1/(8*sqrt(2));\n",
+"printf('\nc1= %.4f',c1);\n",
+"disp('Number of atoms per m^2 = (0.084/r^2)');\n",
+"disp('i)For (111) plane');\n",
+"c2 = 1/(2*sqrt(3));\n",
+"printf('\nc2= %.4f',c2);\n",
+"disp('Number of atoms per m^2 = (0.2887/r^2)');\n",
+"\n",
+"\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.18: Ionic_packing_factor.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.18\n",
+"//Page No.194.\n",
+"clc;clear;\n",
+"r = 0.97*10^(-10);\n",
+"R = 1.81*10^(-10);\n",
+"Pd = ((%pi)/(3*sqrt(2)));\n",
+"printf('\nThe packing density is %.2f',Pd);\n",
+"//Ionic factor of NaCl//\n",
+"IPF = (4*(4/3)*%pi*(r^(3)+R^(3)))/((2*(r+R))^(3));//Ionic packing factor of NaCl crystal.\n",
+"printf('\nThe ionic packing factor of NaCl crystal is %.3f',IPF);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.1: Density_of_diamond.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.1\n",
+"//Page No.185.\n",
+"clc;clear;\n",
+"Mc = 12;// Mc is the mass of one carbon atom.\n",
+"r = 0.071*10^(-9);//radius -[m].\n",
+"D = ((8*Mc)/(6.022*10^(26)*((8*r)/(sqrt(3)))^(3)));//density of the diamond.\n",
+"printf('\nThe density of diamond is %.1f kg/m^3',D);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.2: percentage_volume.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.2.\n",
+"//Page No.185.\n",
+"clc;clear;\n",
+"a1 = 0.332*10^(-9);//Lattice parameter for BCC structure -[m].\n",
+"a2 = 0.296*10^(-9);//Lattice parameter for HCP structure -[m].\n",
+"c = 0.468*10^(-9);// -[m]\n",
+"disp('BCCv is the volume of BCC unit cell');\n",
+"BCCv = a1^(3);//Volume of BCC unit cell.\n",
+"printf('\nThe volume of BCC unit cell is %3.3e m^-3',BCCv);\n",
+"disp('HCPv is the volume of HCP unit cell');\n",
+"HCPv = (6*(sqrt(3)/4)*a2^(2)*c);//Volume of HCP unit cell.\n",
+"printf('\nThe volume of HCP unit cell is %3.3e m^3',HCPv);\n",
+"Cv = (HCPv-BCCv);\n",
+"printf('\nThe change in volume is %3.3e',Cv);\n",
+"Vp = (Cv/BCCv)*100;\n",
+"printf('\nThe volume change in percentage is %.1f percent',Vp);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.3: Atomic_structure_and_density.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.3\n",
+"//Page No.186.\n",
+"clc;clear;\n",
+"r = 1.278*10^(-10);//Atomic radius of copper -[m].\n",
+"A = 63.54;//Atomic weight of copper.\n",
+"n = 4;\n",
+"Na = 6.022*10^(26);\n",
+"a = (2*sqrt(2)*r);\n",
+"printf('\nThe lattice constant for FCC is %3.3e',a); \n",
+"d = ((n*A)/(Na*a^(3)));//for FCCn=4.\n",
+"d = ((n*A)/(Na*(3.61*10^(-10))^(3)));\n",
+"printf('\nThe density of copper is %.0f kg/m^3',d);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.4: Interatomic_distance_of_NACL.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.4.\n",
+"//Page No.186.\n",
+"clc;clear;\n",
+"Na = 23;//Atomic weight of Na\n",
+"Cl = 35.5;//Atomic weight of Cl\n",
+"d = 2180;//Density of Nacl -[kg/m^3].\n",
+"nA = 6.022*10^(26);\n",
+"NaCl = (Na+Cl)//Molecular weight of NaCl.\n",
+"printf('\n1) Molecular weigth of NaCl is %.1f',NaCl);\n",
+"n = 4;\n",
+"A = 58.5;\n",
+"a = (((n*A)/(nA*d))^(1/3));\n",
+"printf('\n2) The interatomic distance of NaCl crystal is %3.3e m',a); "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.5: Relation_between_interatomic_and_interplanar.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.5.\n",
+"//Page No.187.\n",
+"clc;clear;\n",
+"a = 0.42;//Lattice constant -[nm].\n",
+"//(h1,k1,l1) are the miller indices of the plane (101).\n",
+"h1 = 1;\n",
+"k1 = 0;\n",
+"l1 = 1;\n",
+"d1 = (a/sqrt(h1^(2)+k1^(2)+l1^(2)));//interplanar and interatomic distance of plane (101)\n",
+"printf('\nFor (101) plane, the interplanar and interatomic distance is %.4f nm',d1);\n",
+"// (h2,k2,l2) are the miller indices of the plane (221).\n",
+"h2 = 2;\n",
+"k2 = 2;\n",
+"l2 = 1;\n",
+"d2 = (a/sqrt(h2^(2)+k2^(2)+l2^(2)));//interplanar and interatomic distance of plane (221)\n",
+"printf('\nFor (221) plane, the interplanar and interatomic distance is %.2f nm',d2);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.6: Axial_intercepts.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.6.\n",
+"// Page No.187.\n",
+"clc;clear;\n",
+"disp('For the plane (102),the intercepts are (a/1) = a,(b/0) = infinity ,c/2');\n",
+"disp('For the plane (231),the intercepts are a/2 , b/3 and (c/1) = c');\n",
+"disp('For the plane (312),the intercepts are a/3 ,(b/-1) = -b ,c/2');\n",
+"\n",
+"//As there are no numerical steps available and hence the display statement has been typed directly.\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.7: Angle_between_the_planes.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.7\n",
+"//Page No.188.\n",
+"//Find the angle between two planes (111) and (212) in a cubic lattice.\n",
+"clc;clear;\n",
+"// (u1,v1,w1) are the miller indices of the plane (111).\n",
+"u1 = 1;\n",
+"v1 = 1;\n",
+"w1 = 1;\n",
+"// (u2,v2,w2) are the miller indices of the plane (212).\n",
+"u2 = 2;\n",
+"v2 = 1;\n",
+"w2 = 2;\n",
+"u = acosd(((u1*u2)+(v1*v2)+(w1*w2))/((sqrt((u1^2)+(v1^2)+(w1^2))*sqrt((u2^2)+(v2^2)+(w2^2)))));//u is the angle between two planes.\n",
+"printf('\n The angle between the planes (111) and (212) is %.3f degree',u);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.8: Crystallographic_planes.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"// Example No.6.8.\n",
+"// Page No.188.\n",
+"clc;clear;\n",
+"disp('The intercepts of the plane(100) are a ,infinity ,infinity.');\n",
+"disp('The intercepts of the cubic plane(110) are a ,a ,infinity.');\n",
+"disp('The intercepts of the plane(111) are a ,a ,a.');\n",
+"disp('The intercepts of the plane(200) are a/2 ,infinity ,infinity.');\n",
+"disp('The intercepts of the plane(120) are a ,a/2 ,infinity.');\n",
+"disp('The intercepts of the plane(211) are a/2 ,a ,a.');\n",
+"\n",
+"//As there are no numerical steps and hence the display statement has been typed directly.\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.9: Lattice_constant.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.6.9.\n",
+"//Page No.189.\n",
+"clc;clear;\n",
+"d = 0.2338;//'d' is the interplanar distance -[nm].\n",
+"// (h,k,l) are the miller indices of the given plane.\n",
+"h = (-1);\n",
+"k = 1;\n",
+"l = 1;\n",
+"a = (d*sqrt(h^2+k^2+l^2));//'a' is the lattice constant\n",
+"printf('\nThe lattice constant is %.4f nm',a); "
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/7-Crystal_imperfection.ipynb b/Engineering_Physics_by_A_Marikani/7-Crystal_imperfection.ipynb
new file mode 100644
index 0000000..fdb6bbc
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/7-Crystal_imperfection.ipynb
@@ -0,0 +1,140 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 7: Crystal imperfection"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.1: Number_of_vacancies_and_vacancy_fraction.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.7.1\n",
+"//Page No.207\n",
+"//To find number of vacancies.\n",
+"clc;clear;\n",
+"Av = 6.022*10^(26);//Avogadro's constant.\n",
+"d = 18630;//Density.\n",
+"Aw = 196.9;//Atomic weight -[g/mol].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"T = 900;//Temperature.\n",
+"Ev = 0.98*1.6*10^(-19);//Energy of formation.\n",
+"N = ((Av*d)/Aw);//Concentration of atoms.\n",
+"printf('\nConcentration of atoms = %3.3e m^-3',N);\n",
+"n = N*exp(-(Ev)/(k*T));//'n' is number of vacancy.\n",
+"printf('\nThe number of vacancies for gold at 900 degree celcius is %3.3e vacancies per m^3',n);\n",
+"T1 = 1000;\n",
+"Vf = exp((-Ev)/(k*T1));//p=(n/N) is the vacancy fraction.\n",
+"printf('\nVacancy fraction = %3.3e',Vf);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.2: Energy_for_vacancy_information.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.7.2\n",
+"//Page No.208.\n",
+"//To find energy for vacancy information.\n",
+"clc;clear;\n",
+"Av = 6.022*10^(26);//Avogadro's constant.\n",
+"d = 9500;//Density.\n",
+"Aw = 107.9;//Atomic weight -[g/mol].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"T = 1073;//Temperature -[K]\n",
+"n = 3.6*10^(23);//Number of vacancies -[per m^3].\n",
+"N = ((Av*d)/Aw);//Concentration of atoms.\n",
+"printf('\nConcentration of atoms is %3.3e m^-3',N);\n",
+"Ev = k*T*log(N/n);\n",
+"printf('\nThe energy for vacancy formation in joules is %3.3e J',Ev);\n",
+"Ev = Ev/1.6*10^(19);\n",
+"printf('\nThe energy for vacancy formation in eV is %3.3e eV',Ev);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.3: number_of_schottky_defected.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"//Example No.7.3\n",
+"//Page No.209.\n",
+"//To find number of Schottky defected.\n",
+"clc;clear;\n",
+"Av = 6.022*10^(26);//Avogadro's constant.\n",
+"d = 1955;//Density.\n",
+"Aw = (39.1+35.45);//Atomic weight.\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"T = 773;//Temperature -[K]\n",
+"Es = 2.6*1.6*10^(-19);//Energy formation.\n",
+"N = ((Av*d)/Aw);//Concentration of atoms.\n",
+"printf('\nConcentration of atoms is %3.3e m^-3',N);\n",
+"n = N*exp(-(Es)/(2*k*T));\n",
+"printf('\nThe number of Schottky defect for KCl at 500 degree celcius is %3.3e Schottky defect per m^-3',n);\n",
+""
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/8-Conducting_materials.ipynb b/Engineering_Physics_by_A_Marikani/8-Conducting_materials.ipynb
new file mode 100644
index 0000000..52eabbb
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/8-Conducting_materials.ipynb
@@ -0,0 +1,340 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 8: Conducting materials"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.10: Lorentz_number.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.10.\n",
+"//Page No.234.\n",
+"clc;clear;\n",
+"K = 387;//Thermal conductivity of copper -[W m^-1 K^-1].\n",
+"d = 5.82*10^(7);//Electrical conductivity of copper -[ohm^-1 m^-1].\n",
+"T = 300;//Temperature -[K].\n",
+"L = (K/(d*T));\n",
+"printf('\nThe Lorentz number is %3.3e W ohm K^-2',L);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.11: conductivity_and_Larentz_number.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.11.\n",
+"//Page No.235.\n",
+"clc;clear;\n",
+"n = 8.49*10^(28);//Concentration of electrons in copper -[m^-3].\n",
+"e = 1.6*10^(-19);//Value of electron.\n",
+"Tr = 2.44*10^(-14);//Relaxation time of electron -[s]\n",
+"m = 9.1*10^(-31);//mass of electron.\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"T = 293;//Temperature -[K].\n",
+"d = ((n*e^(2)*Tr)/(m));\n",
+"printf('\n1)The electrical conductivity is %3.3e per ohm meter',d);\n",
+"K = ((n*(%pi)^(2)*k^(2)*T*Tr)/(3*m));\n",
+"printf('\n 2)The thermal conductivity is %.2f W m^-1.K^-1',K);\n",
+"L = K/(d*T);\n",
+"printf('\n3)The Lorentz number is %3.3e W ohm K^-2',L);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.1: Resistivity_of_sodium.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.1\n",
+"//Page No.231.\n",
+"clc;clear;\n",
+"m = 9.1*10^(-31);//mass\n",
+"n = 2.533*10^(28);//concentration of electrons -[per m^3]\n",
+"e = 1.6*10^(-19);//Value of electron.\n",
+"Tr = 3.1*10^(-14);//Relaxation time -[s].\n",
+"d = m/(n*e^(2)*Tr);//The resistivity of sodium at 0 degree celcius.\n",
+"printf('\nThe resistivity of sodium at 0 degree celcius is %3.3e ohm m',d);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.2: Band_gap.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.2.\n",
+"//Page No.231.\n",
+"clc;clear;\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"slope = 3.75*10^(3);\n",
+"Eg = ((2*k)*slope)/(1.6*10^(-19));//The band gap of the semiconductor.\n",
+"printf('\nThe band gap of the semiconductor is %.3f eV',Eg);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.3: Probability_of_electro.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.3.\n",
+"//Page No.231.\n",
+"clc;clear;\n",
+"T = 1262;//Temperature -[K].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"E = 0.5*1.6*10^(-19);//Here E= E-Ef.\n",
+"f = 1/(1+exp(E/(k*T)));//'f' is the probability  of occupation of electron at 989 degree celcius.\n",
+"printf('\nThe probability  of occupation of electron at 989 degree celcius is %.2f',f);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.4: Drift_velocity.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example No.8.4.\n",
+"//Page No.232.\n",
+"clc;clear;\n",
+"ue = 0.0035*10^(3);// mobility of electron\n",
+"E = 0.5;//Electric field strength\n",
+"vd = ue*E;\n",
+"printf('\nThe drift velocity of the electron is %.2f m/s',vd);\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.5: mobility_of_electro.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example No.8.6.\n",
+"//Page No.232.\n",
+"clc;clear;\n",
+"n = 18.1*10^(28);\n",
+"h = 6.62*10^(-34);//Planck's constant.\n",
+"m = 9.1*10^(-31);//mass\n",
+"Efo = (h^(2)/(8*m))*(((3*n)/(%pi))^(2/3));//The fermi energy level at 0 k.\n",
+"printf('\nThe Fermi energy of Al at 0 k in joules is %3.3e J',Efo);\n",
+"Efo = (Efo/(1.6*10^(-19)));\n",
+"printf('\nThe Fermi energy of Al at 0 k in eV is %3.3e eV',Efo);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.6: Fermi_energy_level.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.6.\n",
+"//Page No.232.\n",
+"clc;clear;\n",
+"n = 18.1*10^(28);\n",
+"h = 6.62*10^(-34);//Planck's constant.\n",
+"m = 9.1*10^(-31);//mass of electron\n",
+"Efo = (h^(2)/(8*m))*(((3*n)/(%pi))^(2/3));//The fermi energy level at 0 k.\n",
+"printf('\nFermi energy of Al at 0 k in joules = %3.3e J',Efo);\n",
+"Efo = (Efo/(1.6*10^(-19)));\n",
+"printf('\nFermi energy of Al at 0 k in eV = %.2fe eV',Efo);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.7: concentration_of_electrons.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example No.8.7.\n",
+"//Page No.233.\n",
+"clc;clear;\n",
+"h = 6.62*10^(-34);//Planck's constant -[J s].\n",
+"m = 9.1*10^(-31);//mass -[kg].\n",
+"Efo = 5.5*1.6*10^(-19);//Fermi energy.\n",
+"n = ((2*m*Efo)^(3/2))*(8*(%pi))/(3*(h^(3)));\n",
+"printf('\nThe concentration of free electrons per unit volume of silver is %3.3e m^-3',n);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.8: probability_of_electro.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Example No.8.8.\n",
+"//Page No.233.\n",
+"clc;clear;\n",
+"T = 298;//Temperature -[K].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"Eg = 1.07*1.6*10^(-19);//Here E= E-Eg.\n",
+"f = 1/(1+exp(Eg/(2*k*T)));//probability of an electron to the conduction band at 25 degree celcius.\n",
+"printf('\nThe probability of an electron thermlly excited to the conduction band at 25 degree celcius is %3.3e',f);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.9: fermi_energy_and_fermi_temperature.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.8.9.\n",
+"//Page No.234.\n",
+"clc;clear;\n",
+"m = 9.1*10^(-31);//mass of electron.\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"vf = 0.86*10^(6);//Fermi velocity -[m s^-1].\n",
+"Ef = 0.5*m*vf^(2);//Fermi energy \n",
+"printf('\nThe Fermi energy of the metal in joules is %3.3e J',Ef);\n",
+"Ef = Ef/(1.6*10^(-19));\n",
+"printf('\nThe Fermi energy o the metal in eV is %.2f eV',Ef);\n",
+"Tf = ((Ef)/k);//Fermi temperature.\n",
+"Tf = ((3.365*10^(-19))/k);\n",
+"printf('\nThe Fermi temperature of the metal is %3.3e K',Tf);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Engineering_Physics_by_A_Marikani/9-Semiconducting_materials.ipynb b/Engineering_Physics_by_A_Marikani/9-Semiconducting_materials.ipynb
new file mode 100644
index 0000000..e2df71d
--- /dev/null
+++ b/Engineering_Physics_by_A_Marikani/9-Semiconducting_materials.ipynb
@@ -0,0 +1,375 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 9: Semiconducting materials"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.10: Intrinsic_carrier_concentration.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.10.\n",
+"//Page No 272.\n",
+"clc;clear;\n",
+"d = 10^(-6);//Electrical conductivity -[ohm^-1 m^-1].\n",
+"e = 1.6*10^(-19);//Electron charge.\n",
+"ue = 0.85;//Electron mobility -[m^2 V^-1 s^-1].\n",
+"uh = 0.04;//hole mobility -[m^2 V^-1 s^-1].\n",
+"Ni = (d/(e*(ue+uh)));//intrinsic carrier concentration\n",
+"printf('\nThe intrinsic carrier concentration of GaAs is %3.3e m^-3',Ni);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.11: Concentrations.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"\n",
+"\n",
+"//Example No.9.11.\n",
+"//Page No 272.\n",
+"clc;clear;\n",
+"p = 0.1;//Resistivity of P-type and N-type -[ohm m].\n",
+"e = 1.6*10^(-19);//Electron charge.\n",
+"Uh = 0.48;//Hole mobility -[m^2 V^-1 s^-1].\n",
+"Ue = 1.35;//Electron mobility -[m^2 V^-1 s^-1].\n",
+"ni = 1.5*10^(16);\n",
+"d = (1/p);//Electrical conductivity\n",
+"disp('For P-type material')\n",
+"printf('\n1)The electrical conductivity is %.1f ohm^-1 m^-1',d);\n",
+"Na = (d/(e*Uh));//Acceptor concentration.\n",
+"printf('\n2)The acceptor concentration is %3.3e m^-3',Na);\n",
+"n1 = (((ni)^(2))/(Na));//Minority carriers concentration.\n",
+"printf('\n3)The minority carriers concentration is %3.3e m^-3',n1);\n",
+"disp('For N-type semiconductor')\n",
+"d = (1/p);//Electrical conductivity.\n",
+"printf('\n2)The electrical conductivity is %.1f ohm^-1 m^-1',d);\n",
+"Nd = (d/(e*Ue));//Donor concentration.\n",
+"printf('\n2)The donor concentration is %3.3e m^-3',Nd);\n",
+"n2 = (((ni)^(2))/(Nd));//Minority carriers concentration.\n",
+"printf('\n3)The minority carriers concentration  is %3.3e m^-3',n2);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.1: Number_of_charge_carrier.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.1.\n",
+"//Page No.266.\n",
+"//To find number of charge carrier.\n",
+"clc;clear;\n",
+"d = 2.2;//Conductivity -[ohm^-1 m^-1].\n",
+"e = 1.6*10^(-19);//Value of electron.\n",
+"u1 = 0.36;//Mobility of the electrons -[m^2 V^-1 s^-1].\n",
+"u2 = 0.14;//Mobility of the holes -[m^2 V^-1 s^-1].\n",
+"T = 300;//Temperature -[K].\n",
+"n = (d/(e*(u1+u2)));//Number of charge carriers\n",
+"printf('\nThe carrier concentration of an intrinsic semiconductor is %3.3e m^3',n);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.2: Band_gap.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.2.\n",
+"//Page No.266.\n",
+"//To find conductivity of semiconductor.\n",
+"clc;clear;\n",
+"d20 = 250;//Conductivity at 20 degree celcius -[ohm^-1 m^-1].\n",
+"d100 = 1100;//Conductivity at 100 degree celcius -[ohm^-1 m^-1].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"Eg = (2*k*((1/373)-(1/293))^(-1)*log((d20/d100)*(373/293)^(3/2)));//Band gap in joules.\n",
+"printf('\nBand gap of semiconductor in joules is %3.3e J',Eg);\n",
+"Eg = Eg/(1.6*10^(-19));//band gap in eV.\n",
+"printf('\nBand gap of semiconductor in eV is %.4f eV',Eg);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.3: Hall_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.3.\n",
+"//Page No.267.\n",
+"clc;clear;\n",
+"B = 0.5;//Magnetic field -[Wb/m^2].\n",
+"I = 10^(-2);//Current -[A].\n",
+"l = 100;//Length -[mm].\n",
+"d = 1;//Thickness -[mm].\n",
+"Rh = 3.66*10^(-4);//Hall coefficient -[m^3/C].\n",
+"w = 10*10^(-3);//Breadth -[mm].\n",
+"Vh = ((B*I*Rh)/w);//Hall voltage.\n",
+"printf('\nThe Hall voltage is %3.3e V',Vh);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.4: Concentration_of_holes_and_electrons.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.4.\n",
+"//Page No.268.\n",
+"clc;clear;\n",
+"d = 3*10^(4);//Conductivity -[S/m].\n",
+"e = 1.6*10^(-19);//Value of electron.\n",
+"ue = 0.13;\n",
+"uh = 0.05;\n",
+"ni = 1.5*10^(16);\n",
+"disp('For N-type semiconductor')\n",
+"Nd = (d/(e*ue));\n",
+"printf('\ni)The concentration of electron is %3.3e m^-3',Nd);\n",
+"p = ((ni)^(2)/(Nd));\n",
+"printf('\nii)The concentration of holes is %3.3e m^-3',p);\n",
+"disp('For P-type semiconductor')\n",
+"Na = (d/(e*uh));\n",
+"printf('\ni)The concentration of holes is %3.3e m^-3',Na);\n",
+"n = ((ni)^(2)/(Na));\n",
+"printf('\nii)The concentration of electron is %3.3e m^-3',n);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.5: carrier_concentration_and_type_of_carrier.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.5.\n",
+"//Page No.269.\n",
+"//To calculate carrier concentration.\n",
+"clc;clear;\n",
+"Rh = 3.68*10^(-5);//Hall coefficient -[m^3/C].\n",
+"e = 1.6*10^(-19);//Electron charge -[C].\n",
+"disp('1)Since the hall voltage is negative,charge carriers of the semiconductors are electrons')\n",
+"n = ((3*%pi)/(8*Rh*e));//Carrier concentration.\n",
+"printf('\n2)The carrier concentration is %3.3e m^-3',n);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.6: Intrinsic_carrier_densities.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.6.\n",
+"//Page No.269.\n",
+"clc;clear;\n",
+"Eg1 = 0.36;//Energy gap of the first material -[eV].\n",
+"Eg2 = 0.72//Energy gap of the second material -[eV].\n",
+"me = 9.1*10^(-31);// -[kg].\n",
+"A = 0.052;//'A'  is (2*k*T).\n",
+"T = 300;//Temperature -[K].\n",
+"a = -0.36;\n",
+"b = 0.72;\n",
+"N = (exp(a/A)*exp(b/A));//Ratio of intrinsic carrier densities of material A & B.\n",
+"printf('\nThe ratio of intrinsic carrier densities of the materials A & B is %3.3e',N);\n",
+"\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.7: Mobility_of_electro.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.7.\n",
+"//Page No.270.\n",
+"//To find mobility of the electron.\n",
+"clc;clear;\n",
+"d = 112;//Conductivity -[ohm^-1 m^-1].\n",
+"Nd = 2*10^(22);//Concentration of electrons -[m^-3].\n",
+"e = 1.6*10^(-19);//Electron charge.\n",
+"u = (d/(Nd*e));//Mobility of electrons.\n",
+"printf('\nMobility of the electron is %.3f m^2 V^-1 s^-1',u);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.8: hall_voltage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.8.\n",
+"//Page No.270.\n",
+"clc;clear;\n",
+"Bz = 10*10^(-4);//Magnetic field -[Wb/m^2].\n",
+"I = 1;//Current -[A].\n",
+"W = 500*10^(-6);//Thickness of the sample -[m].\n",
+"n = 10^(16);//Donor concentration.\n",
+"e = 1.6*10^(-19);//Electron charge.\n",
+"VH = ((Bz*I*3*%pi)/(8*n*e*W));//Hall voltage in the sample.\n",
+"printf('\nThe Hall voltage in the sample is %3.3e V',VH);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.9: Ratio_between_the_conductivity_of_the_material.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"\n",
+"//Example No.9.9.\n",
+"//Page No 271.\n",
+"clc;clear;\n",
+"Eg = 1.2*1.6*10^(-19);//Energy gap.\n",
+"T1 = 300;//Temperature T1 -[K].\n",
+"T2 = 600;//Temperature T2 -[K].\n",
+"k = 1.38*10^(-23);//Boltzman's constant.\n",
+"N = ((T2/T1)^(3/2))*exp((Eg/(2*k))*((1/T1)-(1/T2)))*10^(-3);//Ratio between  the conductivity of the material.\n",
+"printf('\nRatio between  the conductivity of the material at 600 K and 300 K is %.2f',N);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}