In [1]:

```
import math
# Variables
h = 6.62*10**-34; #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
e = 1.6*10**-19; #electron charge(in coulomb)
Wavelength_1 = 2300*10**-10;
Wavelength_2 = 1800*10**-10;
# Calculation
W = h*c/Wavelength_1; #Work function
E_in = h*c/Wavelength_2;
E = E_in-W; #kinetic energy of the ejected electron(in Joules)
E_1 = E/e; #kinetic energy of the ejected electron(in eV)
# Results
print 'kinetic energy of the ejected electron in = %.1f eV'%E_1
```

In [2]:

```
import math
# Variables
h = 6.625*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
e = 1.602*10**-19; #electron charge(in coulomb)
W = 2.3; #work (in eV)
# Calculation
W_1 = W*e; #work (in joules)
v_o = W_1/h; #threshold frequency(in Hz)
Wavelength = (h*c/W_1)/10**(-10); #Wavelength in Angstrom
# Results
print 'threshold frequency(Hz) = %.2e'%v_o
print 'Wavelength in %.0f Angstrom'%(round(Wavelength,-1))
```

In [6]:

```
import math
# Variables
h = 6.625*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
e = 1.602*10**-19; #electron charge(in coulomb)
# Calculation
wavelength = 6800*10**-10; #wavelength of radiation
v_o = c/wavelength; #frequency
W = h*v_o; #Work function
# Results
print 'threshold frequency in = %.2e Hz'%v_o
print 'work function of metal in = %.2e joule'%W
```

In [3]:

```
import math
# Variables
h = 6.625*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3.*10**8; #speed of light (in m/s)
# Calculation
L_r = 150*8./100; #Lamp rating(in joule)
wavelength = 4500.*10**-10; #in meter
W = h*c/wavelength; #work function
N = L_r/W; #number of photons emitted by lamp per second
# Results
print 'number of photons emitted by lamp per second = %.1e'%N
```

In [1]:

```
import math
# Variables
h = 6.6*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
e = 1.6*10**-19; #electron charge(in coulomb)
W = 2.24; #work function(in eV)
# Calculation
W_1 = W*e; #work function(in joule)
v = (W_1/h)*10**-10; #frequency
wavelength = c/v; #region of electrons spectrum is less than(in angstrom)
# Results
print 'region of electrons spectrum is less than %d angstrom'%round(wavelength,-1)
```

In [7]:

```
import math
# Variables
h = 6.625*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
P_o = 10*10**3; #Power of radio receiver (in Watt)
# Calculation
v = 440*10**3; #Operating frequency
E = h*v; #Energy of each electron
N = P_o/E; #Number of photons emitted/sec
# Results
print 'Number of photons emitted/sec by radio receiver = %.1e'%N
```

In [12]:

```
import math
# Variables
W_t = 4.52; #Work function for tungesten(in eV)
W_b = 2.5; #Work function for barrium(in eV)
h = 6.62*(10**(-34)); #Planck's constant(in m2*kg/s)
c = 3*10**8; #speed of light (in m/s)
# Calculation
e = 1.6*10**-19; #electron charge(in coulomb)
W_T = W_t*e; #Work function for tungesten(in Joule)
W_B = W_b*e; #Work function for barrium(in Joule)
Wavelength_T = (h*c/W_T)*10**10; #wavelength of light which can just eject electron from tungsten
Wavelength_B = (h*c/W_B)*10**10; #wavelength of light which can just eject electron from barrium
# Results
print 'wavelength of light which can just eject electron from tungsten in = %.0f Angstrom'%Wavelength_T
print 'wavelength of light which can just eject electron from barrium in = %.0f Angstrom'%Wavelength_B
```