Q.1
The p-type semiconductor is obtained by doping the intrinsic semiconductor with
  • pentavalent impurities
  • bivalent impurities
  • trivalent impurities
  • any impurity atoms
Q.2
How is population inversion achieved in Carbon dioxide laser?
  • optical pumping
  • by electrical discharge
  • chemical pumping
  • none of the above
Q.3
The concept of matter wave was suggested by_________
  • Heisenberg
  • Louis de Broglie
  • Schrodinger
  • Einstein
Q.4
At 0 kelvin, all the energy levels below fermi level are
  • Completely empty
  • Completely filled
  • Partially filled
  • Half filled
Q.5
Which is NOT a characteristic of a LASER?
  • High intensity
  • unidirectional
  • White light
  • Coherent
Q.6
Which of the following equation represents Simple Harmonic motion?
  • y=mx+c
  • x= a sin wt
  • y = Aebt
  • x= a (wt)
Q.7
At resonance,
  • the natural frequency becomes equal to applied force frequency
  • The amplitude becomes maximum
  • damping becomes minimum
  • all the three options
Q.8
Laser is a monochromatic source of light. This means all the light waves have...
  • same wavelength
  • same phase
  • same intensity
  • same direction
Q.9
In spontaneous emission the incident and emitted waves are...
  • similar
  • different
  • amplified
  • coherent
Q.10
The resonator consists of ... mirrors at least.
  • 2
  • 3
  • 4
  • 5
Q.11
The first laser was built in...
  • 1920
  • 1940
  • 1960
  • 1980
Q.12
The process in which the electrons in the ground state are vibrated to the excited states by providing extra energy from energy sources is called as
  • Population Inversion
  • Spontaneous emission
  • Stimulated emission
  • Pumping
Q.13
In He-Ne laser active energy levels for transitions are provided by
  • Ne atoms
  • He atoms
  • Both He and Ne
  • Co2 atoms
Q.14
We get continuous laser from
  • Ruby
  • Diode
  • He-Ne
  • Co2
Q.15
We get pulse laser from
  • Ruby rod
  • He, Ne laser 10:1 ratio
  • CO2 laser
  • Diode laser
Q.16
In Physics lab the laser we use is
  • He-Ne laser
  • Ruby laser
  • Diode laser
  • Co2 laser
Q.17
Which of the following statements are true?LASER is used as optical source in single mode fibers.LASER lights are highly incoherent.
  • 1. is true and 2. is false
  • 1. is false and 2. is true
  • Both 1 & 2 are true
  • Both 1 & 2 are false
Q.18
The coherent nature of light from LASER is due to
  • Spontaneous emission
  • Stimulated Emission
  • Absorption
  • Pumping
Q.19
Light amplification in LASER is achieved by
  • Population inversion
  • Stimulated emission
  • Spontaneous emission
  • Pumping
Q.20
Minimum number of energy states required to achieve population inversion is
  • 1
  • 2
  • 3
  • 4
0 h : 0 m : 1 s