initial commit / add all books

30 files changed, 452 insertions, 0 deletions

diff --git a/2720/CH2/EX2.15.1/ex2_15_1.sce b/2720/CH2/EX2.15.1/ex2_15_1.sce
new file mode 100755
index 000000000..8a59353fb
--- /dev/null
+++ b/2720/CH2/EX2.15.1/ex2_15_1.sce
@@ -0,0 +1,12 @@
+//Exa 2.15.1

+clc;

+clear;

+close;

+// Given data

+del_E = 0.3;// in eV

+T1 = 300;// in K

+T2 = 330;// in K

+// del_E = K * T1 * log(N/N_c) where del_E= E_C-E_F

+// del_E1 = K * T2 * log(N/N_c) where del_E1= E_C-E_F at T= 330 °K

+del_E1 = del_E*(T2/T1);// in eV 

+disp("The Fermi level will be "+string(del_E1)+" eV below the conduction band")

diff --git a/2720/CH2/EX2.15.2/ex2_15_2.sce b/2720/CH2/EX2.15.2/ex2_15_2.sce
new file mode 100755
index 000000000..da0100cde
--- /dev/null
+++ b/2720/CH2/EX2.15.2/ex2_15_2.sce
@@ -0,0 +1,13 @@
+//Exa 2.15.2

+clc;

+clear;

+close;

+// Given data

+N_c = 2.8 * 10^19;// in cm^-3

+del_E = 0.25;// fermi energy in eV

+KT = 0.0259;

+f_F = exp(-(del_E)/KT);

+disp(f_F,"The probbaility in the condition band is occupied by an electron is ");

+n_o = N_c * exp(-(del_E)/KT);// in cm^-3

+disp(n_o,"The thermal equilibrium electron concentration in cm^-3 is");

+

diff --git a/2720/CH2/EX2.15.3/ex2_15_3.sce b/2720/CH2/EX2.15.3/ex2_15_3.sce
new file mode 100755
index 000000000..8316237af
--- /dev/null
+++ b/2720/CH2/EX2.15.3/ex2_15_3.sce
@@ -0,0 +1,13 @@
+//Exa2.15.3

+clc;

+clear;

+close;

+// Given data

+T1 = 300;// in K

+T2 = 400;// in K

+del_E = 0.27;// Fermi level in eV

+KT = (0.0259) * (T2/T1);// in eV

+N_v = 1.04 * 10^19;// in cm^-3

+N_v = N_v * (T2/T1)^(3/2);// in cm^-3 

+p_o = N_v * exp(-(del_E)/KT);// in per cm^3

+disp(p_o,"The thermal equilibrium hole concentration in per cm^3 is");

diff --git a/2720/CH2/EX2.16.1/ex2_16_1.sce b/2720/CH2/EX2.16.1/ex2_16_1.sce
new file mode 100755
index 000000000..3f53751b2
--- /dev/null
+++ b/2720/CH2/EX2.16.1/ex2_16_1.sce
@@ -0,0 +1,13 @@
+// Exa 2.16.1

+clc;

+clear;

+close;

+// Given data

+At = 63.5;// atomic weight

+Rho = 1.7*10^-6;// in ohm cm

+d = 8.96;// in gm/cc

+N_A = 6.02*10^23;// in /gm.mole

+e = 1.6*10^-19;// in C

+n = (N_A/At)*d;

+Miu_e = 1/(Rho*n*e);// in cm^2/volt.sec

+disp(Miu_e,"The electron mobility in cm^2/volt-sec is");

diff --git a/2720/CH2/EX2.16.2/ex2_16_2.sce b/2720/CH2/EX2.16.2/ex2_16_2.sce
new file mode 100755
index 000000000..4852795ca
--- /dev/null
+++ b/2720/CH2/EX2.16.2/ex2_16_2.sce
@@ -0,0 +1,22 @@
+// Exa 2.16.2

+clc;

+clear;

+close;

+format('e',9)

+// Given data

+l = 0.1;// in m

+A = 1.7;// in mm^2

+A = A * 10^-6;// in m^2

+R = 0.1;// in ohm

+At = 63.5;// atomic weight

+N_A = 6.02*10^23;

+d = 8.96;// in gm/cc

+n = (N_A/At)*d;// in /cc

+n = n * 10^6;// in /m^3

+//Formula R = Rho*(l/A);

+Rho = (R*A)/l;// in ohm m

+Sigma = 1/Rho;// in mho/m

+e = 1.6*10^-19;

+// Formula Sigma = n*e*Miu_e

+Miu_e = Sigma/(n*e);// in m^2/V.sec

+disp(Miu_e,"The mobility in m^2/V-sec is");

diff --git a/2720/CH2/EX2.16.3/ex2_16_3.sce b/2720/CH2/EX2.16.3/ex2_16_3.sce
new file mode 100755
index 000000000..28ff5f05d
--- /dev/null
+++ b/2720/CH2/EX2.16.3/ex2_16_3.sce
@@ -0,0 +1,20 @@
+// Exa 2.16.3

+clc;

+clear;

+close;

+// Given data

+format('v',7)

+d = 10.5;// in gm/cc

+At = 108;// atomic weight

+N_A = 6.025*10^23;// in /gm mole

+r = 10^-3;// in m

+q = 1.6*10^-19;// in C

+n = (N_A/At)*d;// in /cm^3

+n = n * 10^6;// in /m^3

+A = %pi*((r)^2);// in m^2

+I = 2;// in A

+// I = q*n*A*v;

+v = I/(n*q*A);// in m/s

+disp(v,"The drift velocity in m/s is");

+

+// Note: There is calculation error to find the value of drift velocity (i.e v), so the answer in the book is wrong.

diff --git a/2720/CH2/EX2.16.4/ex2_16_4.sce b/2720/CH2/EX2.16.4/ex2_16_4.sce
new file mode 100755
index 000000000..2627458bc
--- /dev/null
+++ b/2720/CH2/EX2.16.4/ex2_16_4.sce
@@ -0,0 +1,21 @@
+// Exa 2.16.4

+clc;

+clear;

+close;

+format('e',10)

+// Given data

+d = 1.03;// in mm

+d = d *10^-3;// in m

+r = d/2;// in m

+R = 6.51;// in ohm

+l = 300;// in mm

+e = 1.6*10^-19;

+n = 8.4*10^28;// in /m^&3

+A = %pi*r^2;

+// R = Rho*(l/A);

+Rho = (R* A)/l;//in ohm m

+Sigma = 1/Rho;// in mho/m

+disp(Sigma,"The conductivity of copper in mho/m is");

+//Formula sigma = n*e*Miu_e

+Miu_e = Sigma/(n*e);// in m^2/V.sec

+disp(Miu_e,"The mobility in m^2/V-sec is");

diff --git a/2720/CH2/EX2.16.5/ex2_16_5.sce b/2720/CH2/EX2.16.5/ex2_16_5.sce
new file mode 100755
index 000000000..a9a1fb1cd
--- /dev/null
+++ b/2720/CH2/EX2.16.5/ex2_16_5.sce
@@ -0,0 +1,14 @@
+// Exa 2.16.5

+clc;

+clear;

+close;

+format('e',8)

+// Given data

+At = 63.5;// atomic weight

+d = 8.96;// in gm/cc

+Miu_e = 43.28;// in cm^2/V.sec

+N_A = 6.02*10^23;// in /gm mole

+e = 1.6*10^-19;// in C

+n = (N_A/At)*d;// in /cc

+Rho = 1/(n*e*Miu_e);// in ohm-cm

+disp(Rho,"The resistivity in ohm-cm is");

diff --git a/2720/CH2/EX2.17.1/ex2_17_1.sce b/2720/CH2/EX2.17.1/ex2_17_1.sce
new file mode 100755
index 000000000..0b921937e
--- /dev/null
+++ b/2720/CH2/EX2.17.1/ex2_17_1.sce
@@ -0,0 +1,12 @@
+// Exa 2.17.1

+clc;

+clear;

+close;

+format('e',9)

+// Given data

+Mu_e = 1500;// in cm^2/volt sec

+Mu_h = 500;// in cm^2/volt sec

+n_i = 1.6 * 10^10;// in per cm^3

+e = 1.6 * 10^-19;// in C

+Sigma = n_i * (Mu_e + Mu_h) * e;// in mho/cm

+disp(Sigma,"The conductivity of pure semiconductor in mho/cm is");

diff --git a/2720/CH2/EX2.17.2/ex2_17_2.sce b/2720/CH2/EX2.17.2/ex2_17_2.sce
new file mode 100755
index 000000000..1d54cb435
--- /dev/null
+++ b/2720/CH2/EX2.17.2/ex2_17_2.sce
@@ -0,0 +1,10 @@
+// Exa 2.17.2

+clc;

+clear;

+close;

+// Given data

+Rho = 10;// in Ω-cm

+Mu_d = 500;// in cm^2/v.s.

+e = 1.6*10^-19;

+n_d = 1/(Rho * e * Mu_d);// in per cm^3

+disp(n_d,"The number of donor atom must be added to achieve in per cm^3 is ");

diff --git a/2720/CH2/EX2.17.3/ex2_17_3.sce b/2720/CH2/EX2.17.3/ex2_17_3.sce
new file mode 100755
index 000000000..23bf7ef88
--- /dev/null
+++ b/2720/CH2/EX2.17.3/ex2_17_3.sce
@@ -0,0 +1,14 @@
+//Exa 2.17.3

+clc;

+clear;

+close;

+//Given data

+AvagadroNumber = 6.02 * 10^23;// in atoms/gm.mole

+at_Ge = 72.6;// atom weight of Ge

+e = 1.6 * 10^-19;// in C

+D_Ge = 5.32;// density of Ge in gm/c.c

+Mu = 3800;// in cm^2/v.s.

+C_Ge = (AvagadroNumber/at_Ge) * D_Ge;// concentration of Ge atoms in per cm^3

+n_d = C_Ge/10^8;// in per cc

+Sigma = n_d * Mu * e;// in mho/cm

+disp(Sigma,"The conductivity in mho/cm is");

diff --git a/2720/CH2/EX2.17.4/ex2_17_4.sce b/2720/CH2/EX2.17.4/ex2_17_4.sce
new file mode 100755
index 000000000..662ee3f58
--- /dev/null
+++ b/2720/CH2/EX2.17.4/ex2_17_4.sce
@@ -0,0 +1,12 @@
+// Exa2.17.4

+clc;

+clear;

+close;

+// Given data

+Rho = 0.3623 * 10^-3;// in Ohm m

+Sigma = 1/Rho;//in mho/m

+D = 4.42 * 10^28;// Ge density in atom/m^3

+n_d = D / 10^6;// in atom/m^3

+e = 1.6 * 10^-19;// in C

+Mu = Sigma/(n_d * e);// in m^2/V.sec

+disp(Mu,"The mobility of electron in germanium in m^2/V.sec is");

diff --git a/2720/CH2/EX2.17.5/ex2_17_5.sce b/2720/CH2/EX2.17.5/ex2_17_5.sce
new file mode 100755
index 000000000..06266dd42
--- /dev/null
+++ b/2720/CH2/EX2.17.5/ex2_17_5.sce
@@ -0,0 +1,18 @@
+//Exa 2.17.5

+clc;

+clear;

+close;

+// Given data

+AvagadroNumber = 6.025 * 10^26;// in kg.Mole

+W = 72.59;// atomic weight of Ge

+D = 5.36 * 10^3;//density of Ge in kg/m^3

+Rho = 0.42;// resistivity in Ohm m

+e = 1.6 * 10^-19;// in C

+Sigma = 1/Rho;// in mho/m

+n = (AvagadroNumber/W) * D;// number of Ge atoms present per unit volume

+// Holes per unit volume, H = n*10^-6%

+H= n*10^-8;

+a=H;

+// Formula sigma= a*e*Mu_h

+Mu_h = Sigma/(a * e);// in m^2/V.sec

+disp(Mu_h,"Mobility of holes in m^2/V.sec is");

diff --git a/2720/CH2/EX2.17.6/ex2_17_6.sce b/2720/CH2/EX2.17.6/ex2_17_6.sce
new file mode 100755
index 000000000..4ff9b0688
--- /dev/null
+++ b/2720/CH2/EX2.17.6/ex2_17_6.sce
@@ -0,0 +1,20 @@
+//Exa 2.17.6

+clc;

+clear;

+close;

+// Given data

+e = 1.6 * 10^-19;// in C

+n_i = 2 * 10^19;// in /m^3

+Mu_e = 0.36;// in m^2/v.s

+Mu_h = 0.17;// in m^2/v.s

+A = 1 * 10^-4;// in  m^2

+V = 2;//in volts

+l = 0.3;// in mm

+l = l * 10^-3;// in m

+E=V/l;// in volt/m

+Sigma = n_i * e * (Mu_e + Mu_h);// in mho/m

+// J = I/A = Sigma * E

+I= Sigma*E*A;

+disp(I,"The current produced in a small germanium plate in amp is");

+

+ 

diff --git a/2720/CH2/EX2.17.7/ex2_17_7.sce b/2720/CH2/EX2.17.7/ex2_17_7.sce
new file mode 100755
index 000000000..bc487a3f0
--- /dev/null
+++ b/2720/CH2/EX2.17.7/ex2_17_7.sce
@@ -0,0 +1,13 @@
+// Exa 2.17.7

+clc;

+clear;

+close;

+format('e',10)

+// Given data

+D = 4.2 * 10^28;//density of Ge atoms in atoms/m^3

+N_d = D / 10^6;// in atoms/m^3

+e = 1.6 * 10^-19;// in C

+Mu_e = 0.36;// in m^2/vs

+Sigma_n = N_d *  e * Mu_e;// in mho/m

+Rho_n = 1/Sigma_n;// in ohm m

+disp(Rho_n,"The resistivity of drop Ge in ohm m is ");

diff --git a/2720/CH2/EX2.17.8/ex2_17_8.sce b/2720/CH2/EX2.17.8/ex2_17_8.sce
new file mode 100755
index 000000000..8642eff03
--- /dev/null
+++ b/2720/CH2/EX2.17.8/ex2_17_8.sce
@@ -0,0 +1,18 @@
+// Exa 2.17.8

+clc;

+clear;

+close;

+// given data

+e = 1.6 * 10^-19;// in C

+n_i = 1 * 10^19;// in per m^3

+Mu_e = 0.36;// in m^2/volt.sec

+Mu_h = 0.17;// in m^2/volt.sec 

+A = 2;// in cm^2

+A = A * 10^-4;// im m^2

+t = 0.1;// in mm

+t = t * 10^-3;// in m

+V = 4;// in volts

+Sigma_i = n_i * e * (Mu_e + Mu_h);// in mho/m

+J = Sigma_i * (V/t);// in Amp/m^2

+I = J * A;// in Amp

+disp(I,"The current produced in a Ge sample in Amp is");

diff --git a/2720/CH2/EX2.17.9/ex2_17_9.sce b/2720/CH2/EX2.17.9/ex2_17_9.sce
new file mode 100755
index 000000000..039da1318
--- /dev/null
+++ b/2720/CH2/EX2.17.9/ex2_17_9.sce
@@ -0,0 +1,12 @@
+//Exa 2.17.9

+clc;

+clear;

+close;

+format('e',9)

+// Given data

+e = 1.6 * 10^-19;// in C

+Mu_h = 500;// in cm^2/V.s.

+Mu_e = 1500;// in cm^2/V.s.

+n_i = 1.6 * 10^10;// in per cm^3

+Sigma_i = n_i * e * ( Mu_h + Mu_e);// in mho/cm

+disp(Sigma_i,"Conductivity of pure silicon at room temperature in mho/cm is");

diff --git a/2720/CH2/EX2.19.1/ex2_19_1.sce b/2720/CH2/EX2.19.1/ex2_19_1.sce
new file mode 100755
index 000000000..75f052f6b
--- /dev/null
+++ b/2720/CH2/EX2.19.1/ex2_19_1.sce
@@ -0,0 +1,16 @@
+//Exa 2.19.1

+clc;

+clear;

+close;

+//Given data

+l= 0.50*10^-2;// width of ribbon in m

+d= 0.10*10^-3;// thickness of ribbon in m

+A= l*d;// area of ribbon in m^2

+B = 0.8;// in Tesla

+D = 10.5;//density in gm/cc

+I = 2;// in amp

+q = 1.6 * 10^-19;// in C

+n=6*10^28;// number of elec. per m^3

+V_H = ( I * B * d)/(n * q * A);// in volts

+disp(V_H,"The hall Voltage produced in volts is");

+

diff --git a/2720/CH2/EX2.19.2/ex2_19_2.sce b/2720/CH2/EX2.19.2/ex2_19_2.sce
new file mode 100755
index 000000000..2f96601a0
--- /dev/null
+++ b/2720/CH2/EX2.19.2/ex2_19_2.sce
@@ -0,0 +1,20 @@
+//Exa 2.19.2

+clc;

+clear;

+close;

+format('e',8)

+// Given data

+l = 1;// in m

+d = 1;// in cm

+d = d * 10^-2;// in m

+W = 1;// in mm

+W = W * 10^-3;// in m

+A = d * W;// in m^2

+I= 1;// in Amp

+B = 1;// Tesla

+V_H = 0.074 * 10^-6;// in Volts

+Sigma = 5.8 * 10^7;// in mho/m

+R_H = (V_H * A)/(B*I*d);// in m^3/c

+disp(R_H,"The hall coefficient in m^3/c is");

+Mu = Sigma * R_H;// in m^2/volt.sec

+disp(Mu,"The mobility  of electrons in copper in m^2/volt-sec is ");

diff --git a/2720/CH2/EX2.20.1/ex2_20_1.sce b/2720/CH2/EX2.20.1/ex2_20_1.sce
new file mode 100755
index 000000000..1a03e8879
--- /dev/null
+++ b/2720/CH2/EX2.20.1/ex2_20_1.sce
@@ -0,0 +1,11 @@
+//Exa2.20.1

+clc;

+clear;

+close;

+// Given data

+n_i = 1.4 * 10^18;// in /m^3

+n_D = 1.4 * 10^24;// in /m^3

+n=n_D;// in /m^3

+p = n_i^2/n;// in /m^3

+R = n/p;

+disp(R,"The ratio of electrons to hole concentration is");

diff --git a/2720/CH2/EX2.20.2/ex2_20_2.sce b/2720/CH2/EX2.20.2/ex2_20_2.sce
new file mode 100755
index 000000000..6eaf47327
--- /dev/null
+++ b/2720/CH2/EX2.20.2/ex2_20_2.sce
@@ -0,0 +1,11 @@
+//Exa 2.20.2

+clc;

+clear;

+close;

+// Given data

+B = 0.48;// in wb/m^2

+R_H = 3.55 * 10^-4;// in m^3/c

+Rho = 0.00912;// in ohm-m

+Sigma = 1/Rho;// in (ohm-m)^-1

+theta_H = atand( Sigma * B * R_H);// in degree

+disp(theta_H,"The hall angle for a hall coefficient in degree is");

diff --git a/2720/CH2/EX2.20.3/ex2_20_3.sce b/2720/CH2/EX2.20.3/ex2_20_3.sce
new file mode 100755
index 000000000..0dbe2403e
--- /dev/null
+++ b/2720/CH2/EX2.20.3/ex2_20_3.sce
@@ -0,0 +1,15 @@
+//Exa 2.20.3

+clc;

+clear;

+close;

+//Given data

+R = 9 * 10^-3;// in ohm-m

+R_H = 3.6 * 10^-4;// in m^3

+e = 1.6 * 10^-19;// in C

+Sigma = 1/R;// in (ohm-m)^-1

+Rho = 1/R_H;// in coulomb/m^3

+n = Rho/e;// in /m^3

+disp(n,"Density of charge carriers in per m^3 is");

+Mu = Sigma * R_H;// in m^2/v-s

+disp(Mu,"Mobility of charge carriers in m^2/V-s is");

+

diff --git a/2720/CH2/EX2.24.1/ex2_24_1.sce b/2720/CH2/EX2.24.1/ex2_24_1.sce
new file mode 100755
index 000000000..e43c62455
--- /dev/null
+++ b/2720/CH2/EX2.24.1/ex2_24_1.sce
@@ -0,0 +1,12 @@
+//Exa 2.24.1

+clc;

+clear;

+close;

+// Given data

+e = 1.6 * 10^-19;// in C

+R_H = 0.0145;// in m^3/coulomb

+Mu_e = 0.36;// in m^2/v-s

+E = 100;// in V/m

+n = 1/(e * R_H);// in /m^3

+J = n * e * Mu_e * E;// in A/m^2

+disp(J,"The current density of specimen in A/m^2 is");

diff --git a/2720/CH2/EX2.24.2/ex2_24_2.sce b/2720/CH2/EX2.24.2/ex2_24_2.sce
new file mode 100755
index 000000000..a12eb5fb3
--- /dev/null
+++ b/2720/CH2/EX2.24.2/ex2_24_2.sce
@@ -0,0 +1,17 @@
+//Exa 2.24.2

+clc;

+clear;

+close;

+//Given data

+Mu_e = 7.04 * 10^-3;// in m^2/v-s

+m = 9.1 * 10^-31;

+E_F = 5.5;// in eV

+n = 5.8 * 10^28;

+e = 1.6 * 10^-19;// in C

+Torque = (Mu_e/e) * m;// in sec

+disp(Torque,"Relaxation Time in sec is ");

+Rho = 1 /(n * e * Mu_e);// in ohm-m

+disp(Rho,"Resistivity of conductor in ohm-m is ");

+V_F = sqrt((2 * E_F * e)/m);// in m/s

+disp(V_F,"Velocity of electrons with fermi-energy in m/s is");

+

diff --git a/2720/CH2/EX2.24.3/ex2_24_3.sce b/2720/CH2/EX2.24.3/ex2_24_3.sce
new file mode 100755
index 000000000..31a31f318
--- /dev/null
+++ b/2720/CH2/EX2.24.3/ex2_24_3.sce
@@ -0,0 +1,15 @@
+//Exa 2.24.3

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+E= 5.95;// in eV

+EF= 6.25;// in eV

+delE= 0.01;

+ // delE= 1-1/(1+exp((E-EF)/KT))

+K=1.381*10^-23;// Boltzman Constant in J/K

+T = ((E-EF)/log(1/(1-delE) -1)*1.6*10^-19)/K;// in K

+T= round(T)

+disp(T,"The temperature in K is : ")

+ 

diff --git a/2720/CH2/EX2.24.4/ex2_24_4.sce b/2720/CH2/EX2.24.4/ex2_24_4.sce
new file mode 100755
index 000000000..08be8d9d9
--- /dev/null
+++ b/2720/CH2/EX2.24.4/ex2_24_4.sce
@@ -0,0 +1,14 @@
+//Exa 2.24.4

+clc;

+clear;

+close;

+// Given data 

+N_V = 1.04 * 10^19;// in cm^-3

+T1 = 300;// in K

+T2 = 400;// in K

+del_E = 0.27;// in eV

+N_V = N_V * (T2/T1)^1.5;// in cm^-3

+KT = (0.0259) * (T2/T1);// in eV

+P_o = N_V * exp(-(del_E)/KT);// in cm^-3

+disp(P_o,"The thermal equilibrium hole concentration in silicon in cm^-3 is ");

+

diff --git a/2720/CH2/EX2.24.5/ex2_24_5.sce b/2720/CH2/EX2.24.5/ex2_24_5.sce
new file mode 100755
index 000000000..14923f3db
--- /dev/null
+++ b/2720/CH2/EX2.24.5/ex2_24_5.sce
@@ -0,0 +1,17 @@
+//Exa 2.24.5

+clc;

+clear;

+close;

+//Given data

+N_c = 2.8 * 10^19;

+N_V = 1.04 *10^19;

+T1 = 550;// in K

+T2 = 300;// in K

+E_g = 1.12;

+KT = (0.0259) ;

+n_i = sqrt(N_c *N_V *(T1/T2)^3* exp(-(E_g)/KT*T2/T1));// in cm^-3

+// n_o = N_d/2 + sqrt((N_d/2)^2 + (n_i)^2)

+// 1.05*N_d -N_d/2= sqrt((N_d/2)^2 + (n_i)^2)

+N_d=sqrt((n_i)^2/((0.55)^2-1/4));

+disp(N_d,"Minimum donor concentration required in cm^-3 is"); 

+

diff --git a/2720/CH2/EX2.24.6/ex2_24_6.sce b/2720/CH2/EX2.24.6/ex2_24_6.sce
new file mode 100755
index 000000000..e54df4d49
--- /dev/null
+++ b/2720/CH2/EX2.24.6/ex2_24_6.sce
@@ -0,0 +1,20 @@
+//Exa 2.24.6

+clc;

+clear;

+close;

+//Given data

+T = 300;// in K

+n_o = 10^15;// in cm^-3

+n_i = 10^10;// in cm^-3

+p_o = 10^5;// in cm^-3

+del_n = 10^13;// in cm^-3

+del_p = del_n;// in cm^-3

+KT = 0.0259;// in eV

+delta_E1= KT*log(n_o/n_i);// value of E_F-E_Fi in eV

+delta_E2= KT*log((n_o+del_n)/n_i);// value of E_Fn-E_Fi in eV

+delta_E3= KT*log((p_o+del_p)/n_i);// value of E_Fi-E_Fp in eV

+disp(delta_E1,"The Fermi level for thermal equillibrium in eV is : ")

+disp(delta_E2,"The quase-Fermi level for electrons in non equillibrium in eV is : ")

+disp(delta_E3,"The quasi-Fermi level for holes in non equillibrium in eV is : ")

+disp("The quasi-Fermi level for electrons is above E_Fi ")

+disp("While the quasi-Fermi level for holes is below E_Fi")

diff --git a/2720/CH2/EX2.6.1/ex2_6_1.sce b/2720/CH2/EX2.6.1/ex2_6_1.sce
new file mode 100755
index 000000000..dceeb048a
--- /dev/null
+++ b/2720/CH2/EX2.6.1/ex2_6_1.sce
@@ -0,0 +1,14 @@
+// Exa 2.6.1

+clc;

+clear;

+close;

+// Given data

+lembda = 11000;// in Å

+lembda = lembda * 10^-10;// in m

+h = 6.625*10^-34;

+c = 3*10^8;// in m/s

+e = 1.6*10^-19;// in C

+E_g = (h*c)/(lembda*e);// in eV

+disp(E_g,"The energy gap in eV is");

+

+// Note: In the book, there is calculation error to evaluate the value of Eg, so the answer in the book is wrong and the answer of coding is correct.

diff --git a/2720/CH2/EX2.6.2/ex2_6_2.sce b/2720/CH2/EX2.6.2/ex2_6_2.sce
new file mode 100755
index 000000000..35e2c0965
--- /dev/null
+++ b/2720/CH2/EX2.6.2/ex2_6_2.sce
@@ -0,0 +1,13 @@
+// Exa 2.6.2

+clc;

+clear;

+close;

+// Given data

+E_g = 0.75;// in eV

+e = 1.6*10^-19;// in C

+h = 6.63*10^-34;// in J

+c = 3*10^8;// in m/s

+//Formula E_g = (h*c)/(lembda*e);

+lembda = (h*c)/(E_g*e);// in m

+lembda = lembda * 10^10;// in Å

+disp(lembda,"The wavelength in Å is");