Q.1.
Photons emitted by spontaneous emission are __________
- a) Coherent and Monochromatic
- b) Non-coherent and monochromatic
- c) Coherent and Non-Monochromatic
- d) Non-Coherent and Non-monochromatic
Q.2.
In Stimulated Absorption, what is the lifetime of atoms ground state?
- a) 1 second
- b) 1 minute
- c) 1 hour
- d) Infinity
Q.3.
Phonons are __________
- a) Quanta of energy
- b) Quanta of light waves
- c) Quanta of sound waves
- d) Quanta of heat
Q.4.
The frequency of incident photon so that the atom makes a transition from E1 to E2 should be __________
- a) E2 – E1
- b) E2 – E1/c
- c) E2 – E1/h
- d) E2 – E1/λ
Q.5.
What is the general lifetime of an atom in an exited state?
- a) 10-10
- b) 10-8
- c) 10-6
- d) 10-4
Q.6.
The output of a laser has pulse duration ofms and average output power of 1.W per pulse. How much energy is released per pulse if wavelength isÅ?
- a) 0.011 J
- b) 0.024 J
- c) 0.035 J
- d) 0.047 J
Q.7.
Laser light from a 7mW source of aperture diameter 1.5 cm and wavelengthÅ is focused by a lens of focal lengthcm. The intensity of the image is __________
- a) 3 X 107 Wm-2
- b) 4 X 107 Wm-2
- c) 5 X 107 Wm-2
- d) 6 X 107 Wm-2
Q.8.
For an ordinary light source, the coherence time t = 10-10s. The degree of Monochromaticity for a wavelength ofÅ is ___________
- a) 0.1 X 10-4
- b) 0.2 X 10-4
- c) 0.3 X 10-4
- d) 0.4 X 10-4
Q.9.
In Stimulated emission, the emitted photons are _____________
- a) Coherent and Monochromatic
- b) Non-coherent and monochromatic
- c) Coherent and Non-Monochromatic
- d) Non-Coherent and Non-monochromatic
Q.10.
The following graph is pictorial representation of _____________
- a) Spontaneous emission
- b) Spontaneous Absorption
- c) Stimulated emission
- d) Stimulated Absorption