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WorksheetsLaser
Total questions: 51
Worksheet time: 29mins
This situation shows that
light travels in a straight line
light is everywhere
light penetrates certain objects
light is produces by the Sun
Acronym for LASER is
Light Absorption by Stimulated Emission of Radiation
Light Amplification by Stimulated Emission of Radiation
Light Alteration by Stimulated Emission of Radiation
Light Attenuation by Stimulated Emission of Radiation
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
Naturally occuring process in a LASER is
Stimulated Emission
Absorption
Spontaneous Emission
Population Inversion
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
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
Albert Einstein discovered the most important process of the laser. What is it?
Einstein Process
photon emission
medium process
stimulated emission
Pump system needs to raise the atoms from...
exited state to ground state
ground state to exited state
ground state to unexcited state
excited state to exited state
The resonator consists of ... mirrors at least.
2
3
4
5
The first laser was built in...
1920
1940
1960
1980
Population inversion means
Number of atoms in excited state are equal to the number of atoms in the ground state.
Number of atoms in excited state are more than the number of atoms in the ground state.
Number of atoms in excited state are less than the number of atoms in the ground state.
No atom in excited state.
A source is said to be Monochromatic if
light coming from a source has only one frequency.
light coming from a source has two frequency.
Light coming from a source has multiple frequency.
Light coming from a source has multiplewavelength.
Which of the following property is a property of laser?
Directional
Monochromatic
Coherence
Divergent
What is the process responsible for producing photons in diode laser?
Fermi level shift
Majority carrier injection
Carrier freeze out
Electron-hole recombination
What are three types of Laser?
gas,solid,diode
diode,inverted,pointer
gas,metal vapor,rock
pointer,diode,CD
What was the active medium used in the first working laser ever constructed?
helium-neon gas
a diamond block
carbon dioxide gas
a ruby rod
Which of the following is an example of optical pumping?
Ruby laser
Helium-Neon laser
Semiconductor laser
Dye laser
Example of solid state laser is
He-Ne laser
co2 laser
Nd:YAG Laser
Dye laser
A wave is ...
the motion of a disturbance between two points
made up of atoms that travel at the speed of light
water that comes up on the shore
defined as a laser beam
How can lasers remove tattoos from skin?
by burning away skin cells containing tattoo ink
by chemically changing tattoo ink so that it is invisible
by breaking down the molecules that make up the ink
laser tattoo removal is currently impossible
The lowest allowable energy state of an atom is known as what?
ground state
ionized energy
absolute zero
base level
What wavelength did the first laser operate at?
532 nm
694 nm
755 nm
800 nm
The "A" in laser stands for
association
application
amplification
antenna
Which of the following is NOT a common medical use for lasers?
tattoo removal
vision correction
hair removal
hair restoration
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
In Physics lab the laser we use is
He-Ne laser
Ruby laser
Diode laser
Co2 laser
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
Metastable state is
The ground state
Any excited state
an excited state with relatively larger life time
an excited state with relatively smaller life time
In a LASER diode,the light output is taken from
P-layer
N-layer
Active layer
Mirror polished reflecting surface
High optical gain in LASER diode is due to
Heavily doped P-layer
Heavily doped N-layer
Active layer
Reflective surfaces
High optical gain in LASER diode is due to
Heavily doped P-layer
Heavily doped N-layer
Active layer
Reflective surfaces
Laser is made of
Highly coherent photons
Electrons
Neutrons
Very light and elastic particles
The rate of absorption transition Rabs depends on
ρ(ν) and N1
ρ(ν) only
N1 only
none of the above
The rate of spontaneous emission Rsp depends only on
N1
N2
ρ(ν)
none of the above
The rate of stimulated emission Rst depends only on ρ(ν)
True
False
Life time of metastable state is
10-8 s
10-10 s
10-3 s
10-9 s
CO2 laser is a type of
Solid Laser
Liquid Laser
Molecular Gas Laser
Semiconductor Laser
Power output of CO2 laser is
10 kW
10 W
10 microwatt
1 W
Example for direct band gap semiconductors are
GaAs
Ge
Si
AlSb
The wavelength of the emitted radiations depends upon the -----------------------in GaAs semiconductor laser
Refractive Index
Band gap, concentration of donor and acceptor atoms
Current
Resistance
Wavelength produced by smeiconductor laser is
5000 Angstrom
6000 Angstrom
8400 to 8600 Angstrom
None
Holography records _______ of light coming from an object.
Intensity
Phase
Both intensity and phase
None of the above
A recorded holographic plate contains information in the _______ pattern.
interference
diffraction
both a and b
none of the above
If a hologram breaks into pieces, then each piece can produce
Real image
Virtual image
Both virtual and real image
Zero image
An atom is stimulated from the state of energy 1x10-34 J to an excited sate of energy 7.62x10-34 J. Calculate the frequency of the stimulating photon.
2.0364 Hz
3.1042 J
1 Hz
0.5276 Hz
