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WorksheetsENGINEERING PHYSICS
Total questions: 21
Worksheet time: 11mins
Life time of electron in ground state of an atom in seconds
0
equal to half life period
1
Infinite
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
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
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
Find the difference between two energy levels of Neon if the transition levels gives a photon of wl 6328 Angstrom.
3.14 X 10-19 J
3.14 J
3.14 x 10-12 J
1.96 J
In Ruby laser optical pumping is done through
external green light
electric discharge
by heating the system
external red light
In He-Ne laser active energy levels for transitions are provided by
Ne atoms
He atoms
Both He and Ne
Co2 atoms
We get continuous laser from
Ruby
Diode
He-Ne
Co2
We get pulse laser from
Ruby rod
He, Ne laser 10:1 ratio
CO2 laser
Diode laser
In Physics lab the laser we use is
He-Ne laser
Ruby laser
Diode laser
Co2 laser
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
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
The coherent nature of light from LASER is due to
Spontaneous emission
Stimulated Emission
Absorption
Pumping
Light amplification in LASER is achieved by
Population inversion
Stimulated emission
Spontaneous emission
Pumping
Minimum number of energy states required to achieve population inversion is
1
2
3
4
The lifetime of electrons are more in
Pump state
Excited state
Meta stable state
Ground state
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
Laser is a monochromatic source of light. This means all the light waves have...
same wavelength
same phase
same intensity
same direction
In spontaneous emission the incident and emitted waves are...
similar
different
amplified
coherent
The resonator consists of ... mirrors at least.
2
3
4
5
The first laser was built in...
1920
1940
1960
1980
