#Pairs generated per second
import math
#Variable Declaration
lam=0.4*10**-6 # wavelength of light
A=4*10**-6 # area of the crystal
in1=200.0 # intensity of light in W/m^2
h=6.626*10**-34 # Planck's constant
c=3*10**8 # speed of light
#Calculation
N=in1*A*lam/(h*c)
#Result
print('The number of pairs generated per second is %.3f * 10^14'%(N*10**-14))
# Wavelength of emitted radiation
import math
#Variable Declaration
e=1.6*10**-19 # Charge of electron
eg=1.43 # band gap energy in eV
h=6.626*10**-34 # Planck's constant
c=3*10**8 # speed of light in m/s
#Calculation
E=e*eg
lam=h*c/E
#Result
print('The wavelength of emitted radiation is %.2f µm'%(lam*10**6))