Q.1
The lifetime of electrons are more in
  • Pump state
  • Excited state
  • Meta stable state
  • Ground state
Q.2
Laser is a coherent source of light. This means all the light waves....
  • are out of phase
  • are in phase
  • have different directions
  • have same direction
Q.3
In Ruby laser optical pumping is done through
  • external green light
  • electric discharge
  • by heating the system
  • external red light
Q.4
If optical resonator is not formed
  • No output in laser would be there
  • Output would be there but would stop very soon
  • Intensity can't grow
  • No laser would be produced at all
Q.5
According to Einstein at equilibrium
  • Rate of absorption of radiation is equal to rate of stimulated emission
  • Rate of spontaneous emission is equal to rate of stimulated emission
  • Rate of absorption of radiation is equal to rate of spontaneous emission
  • Rate of stimulated emission is constant
Q.6
Population inversion for Lasing action means
  • More electrons in ground state than excited state
  • More electrons in any excited state than ground state
  • More electrons in 1st excited than ground state
  • More electrons in metastable state than ground state
Q.7
Life time of electron in ground state of an atom in seconds
  • 0
  • equal to half life period
  • 1
  • Infinite
Q.8
What is the energy of Photon?
  • E = hνE\ =\ h\nuE = hν
  • E = mc2E\ =\ mc^2E = mc2
  • E = h2ν2E\ =\ h^2\nu^2E = h2ν2
  • E =hmvE\ =\frac{h}{mv}E =mvh​
Q.9
According to J. Maxwell theory Light is an
  • Electromagnetic Wave
  • Acoustic Wave
  • Tidal Wave
  • Longitudinal Wave
0 h : 0 m : 1 s