6 files changed, 114 insertions, 0 deletions
diff --git a/3869/CH4/EX4.1/Ex4_1.sce b/3869/CH4/EX4.1/Ex4_1.sce
new file mode 100644
index 000000000..bc9539cc0
--- /dev/null
+++ b/3869/CH4/EX4.1/Ex4_1.sce
@@ -0,0 +1,20 @@
+clear
+//
+//
+//
+
+//Variable declaration
+c=3*10**8               //velocity of light(m/sec)
+lamda=6943*10**-10      //wavelength(m)
+h=6.626*10**-34         //planck's constant(Jsec)
+Kb=1.38*10**-23         //boltzmann constant
+T=300                   //temperature(K)
+
+//Calculation
+new=c/lamda          //frequency(Hz)
+a=h*new/(Kb*T)
+N1byN2=exp(a)   //relative population
+
+//Result
+printf("\n relative population is %0.3f  *10**30",N1byN2/10**30)
+printf("\n answer given in the book is wrong")
diff --git a/3869/CH4/EX4.2/Ex4_2.sce b/3869/CH4/EX4.2/Ex4_2.sce
new file mode 100644
index 000000000..b0d0277d6
--- /dev/null
+++ b/3869/CH4/EX4.2/Ex4_2.sce
@@ -0,0 +1,21 @@
+clear
+//
+//
+//
+
+//Variable declaration
+c=3*10**8               //velocity of light(m/sec)
+lamda=632.8*10**-9      //wavelength(m)
+h=6.626*10**-34         //planck's constant(Jsec)
+t=1                     //time(sec)
+P=2.3*10**-3            //power(W)
+sa=1*10**-6             //spot area(m**2)
+
+//Calculation
+new=c/lamda             //frequency(Hz)
+n=P*t/(h*new)           //number of photons emitted(per sec) 
+Pd=P/sa                 //power density(kW/m**2)
+
+//Result
+printf("\n number of photons emitted is %0.2f  *10**15 photons/second",n/10**15)
+printf("\n power density is %0.3f  kW/m**2",Pd/10**3)
diff --git a/3869/CH4/EX4.3/Ex4_3.sce b/3869/CH4/EX4.3/Ex4_3.sce
new file mode 100644
index 000000000..d2f9f06a0
--- /dev/null
+++ b/3869/CH4/EX4.3/Ex4_3.sce
@@ -0,0 +1,16 @@
+clear
+//
+//
+//
+
+//Variable declaration
+c=3*10**8               //velocity of light(m/sec)
+e=1.6*10**-19           //charge of electron(coulomb)
+Eg=1.44*e               //band gap energy(J)
+h=6.626*10**-34         //planck's constant(Jsec)
+
+//Calculation
+lamda=h*c/Eg            //wavelength(m)
+
+//Result
+printf("\n wavelength is %0.0f  angstrom",lamda*10**10)
diff --git a/3869/CH4/EX4.4/Ex4_4.sce b/3869/CH4/EX4.4/Ex4_4.sce
new file mode 100644
index 000000000..b34eb7470
--- /dev/null
+++ b/3869/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,13 @@
+clear
+//
+//
+//
+
+//Variable declaration
+lamda=1.55              //peak emission wavelength(micro m) 
+
+//Calculation
+Eg=1.24/lamda           //band gap(eV)
+
+//Result
+printf("\n band gap is %0.3f  eV",Eg)
diff --git a/3869/CH4/EX4.5/Ex4_5.sce b/3869/CH4/EX4.5/Ex4_5.sce
new file mode 100644
index 000000000..c3b1e8604
--- /dev/null
+++ b/3869/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,22 @@
+clear
+//
+//
+//
+
+//Variable declaration
+c=3*10**8               //velocity of light(m/sec)
+e=1.6*10**-19           //charge of electron(coulomb)
+lamda=6943*10**-10      //wavelength(m)
+h=6.6*10**-34           //planck's constant(Jsec)
+kb=1.38*10**-23         //boltzmann constant
+T=300                   //temperature(K)      
+
+//Calculation
+Uv=h*c/(e*lamda)        //energy(eV)
+Uvj=Uv*e                //energy(J)
+x=Uvj/(kb*T)
+NbyN0=exp(x)       //relative population of 2 states
+
+//Result
+printf("\n relative population of 2 states is %0.0f  *10**29",NbyN0*10**-29)
+printf("\n answer given in the book is wrong")
diff --git a/3869/CH4/EX4.6/Ex4_6.sce b/3869/CH4/EX4.6/Ex4_6.sce
new file mode 100644
index 000000000..ccb599d9d
--- /dev/null
+++ b/3869/CH4/EX4.6/Ex4_6.sce
@@ -0,0 +1,22 @@
+clear
+//
+//
+//
+
+//Variable declaration
+c=2.998*10**8               //velocity of light(m/sec)
+lamda=0.5*10**-9            //wavelength(m)
+h=6.626*10**-34             //planck's constant(Jsec)
+Kb=1.381*10**-23            //boltzmann constant
+T=1000                      //temperature(K)
+
+//Calculation
+new=c/lamda                 //operating frequency(Hz)
+new=new/10**3               //operating frequency(kHz)
+new=(new/10**14)*10**14
+
+x=h*new/(Kb*T)
+B21byA21=1/(exp(x)-1)  //ratio of emission  
+
+//Result
+printf("\n ratio of emission is %0.1f  *10**-13",B21byA21*10**13)