WorksheetsUNIT 1
Total questions: 50
Worksheet time: 38mins
How many types of coherence schemes are available?
1
2
3
4
Which one of the following represents the temporal coherence?
Associate with the difference in frequencies of the two waves
Associate with the location of the two waves
Both a and b
None of the above
Which one of the following represents the spatial coherence?
Associate with the difference in frequencies of the two waves
Associate with the location of the two waves
Both a and b
None of the above
Which one of the following is a type of coherence
Q-Switching
Temporal
Direct conversion
Modelocking
Temporal coherence also called as or similar with______
Longitudinal
transverse
Dispersion
Population inversion
Spatial coherence also called as_________
Population inversion
Dispersion
Transverse
Longitudinal
What distribution law will be useful to find the population from the energy levels
Maxwell-Boltmann distribution law
Bose-Einestein distribution law
Fermi-Dirac distribution law
none of the above
In 1917, __________ laid the foundation for the laser when he introduced the concept of stimulated emission
Newton
Scholaw
Tesla
Einstein
In Stimulated Emission, which among the following parameters of a generated photon is/aresimilar to the photon of the incident wave?
Phase
Polarization & direction of travel
Frequency
All of the above
Stimulated absorption is
Transition of atom from lower energy state to higher energy state due to incident photon.
transition of atom from lower energy state to higher energy state without external energy
transition of atom from higher energy state to lower energy state
transition of atom from meta stable state to ground state
Spontaneous emission is
the transition of an atom from a metastable state to the ground state
the transition of an atom from higher energy state to lower energy state
the transition of an atom from lower energy state to higher energy state due to incidentphoton.
the transition of an atom from lower energy state to higher energy state without external energy
Stimulated emission is
the transition of an atom from a higher energy state to a lower energy state due toincident photon.
the transition of an atom from higher energy state to lower energy state
the transition of an atom from a metastable state to the ground state
transition of an atom from lower energy state to higher energy state due to the incidentphoton.
The stimulated emission is
coherent and monochromatic
coherent and polychromatic
polychromatic and unidirectional
polychromatic and high intense
Stimulated emission emits
radiation with a frequency equal to the frequency of the incident light
radiation with a frequency equal to the two times the frequency of the incident light
radiation with a frequency equal to the three times the frequency of the incident light
radiation with frequency equal to the half of the frequency of the incident light
Laser light is intense because
It has very large number of Photons that are not in phase
It has very large number of Photons that are in phase
It has very less number of Photons that in phase
It has very less number of Photons that are not in phase
LASER is a short form of
Light Absorption by Spontaneous Emission of Radiation
Light Absorption by Stimulated Emission of Radiation.
Light Amplification by Stimulated Emission of Radiation.
Light Amplification by Spontaneous Emission of Radiation.
The laser beam is made up of
Excited atoms
Elastic particles
Highly coherent photon
Electrons
Directionality property of laser can be used in
Lidar
remote sensing
surveying
All the above
The number of atoms in the excited state becomes much greater than the number of atoms in the ground state. This is known as
spontaneous emission
stimulated emission
population inversion
normal population
Which characteristic of LASER allows it to be used in holography?
Monochromaticity
Intensity
Directionality
Coherency
Which of the following is not a characteristic of LASERS?
Intense
Coherent
Monochromatic
Divergent
Which of the following is a unique property of laser?
Wavelength
Coherence
Speed
Directional
In Stimulated Absorption, what is the lifetime of atom's ground state?
1 hour
Infinity
1 minute
1 second
What is the need to achieve population inversion?
To reduce the time of production of laser
To achieve stable condition
To bring most of the atoms to ground state
To excite most of the atoms
The laser beam is emitted in the form of
light beam
Intensity
spectrum
Fluctuating radiations
Pumping process will be useful and enables the following one___________
No atoms are available in the excited state.
The number of atoms in the ground state is equal to the number of atoms in the excitedstate.
The number of atoms in the ground state is greater than the number of atoms in theexcited state.
The number of atoms in the excited state is greater than the number of atoms in the ground state
The LASER's are used in DVD. True or False?
True, Used
False, Not used
May be Used
None of the above
Which scientist first came up with the idea of stimulated emission?
Albert Einstein
Arthur Schalow
Isaac Newton
Alexander Graham Bell
Name the scientist who has invented laser.
Albert Einstein
Arthur Schalow
Isaac Newton
T. H.Maiman
Which of the following statements concerning a laser system is incorrect?
Spontaneous emission occurs in the laser system
The laser medium consists of a metastable state
The intensity of the laser beam can be verified by changing the reflective coefficientsof the partially reflecting mirror
The laser system does not require an external energy source
In population inversion the condition of inversion can be written as
N1<N2
N1>N2
N1=N2
N1 & N2 = 1
---------------- in the laser occurs when the photon colliding with an excited atom causes thestimulated emission of a second photon
Population inversion
Dispersion
Attenuation
Light amplification
What is the value of Planck's constant
6.625x 10
-32
Js
1x10
-36
Js
1.625 x10
-34
Js
6.625 x10
-34
Js
What are Einstein’s coefficients?
The coefficients A and B accounts for spontaneous and stimulated emission /absorption probabilities of light by a system of particles.
It also explains the importance of metastable states
Both statements
None of the above
Which of the following is the first LASER?
He-Ne laser
Ruby laser
Argon Laser
Semiconductor Laser
Laser radiation is
Produced with large power densities
Directed in a narrow beam
Monochromatic
All of the above
In the population inversion
The number of electrons in higher energy state is more than the ground state
The number of electrons in lower energy state is more than higher energy state
The number of electrons in lower energy state and higher energy state are same
None of them
The stimulated emission is dominant over-stimulated absorption by the process is called_______ .
Optical Pumping
Population Inversion
Nuclear Energy
None of these
The lower energy level contains more atoms than the upper level under the conditions of
pumping
isothermal packaging
population inversion
thermal equilibrium
The light emitted by ordinary source of light is
Monochromatic
Coherent
Non-coherent
None of these
Optical pumping is the process by which atoms are excited to ………energy states
No effect
Intermediate
Higher
Lower
Laser is a
Perfectly monochromatic source
Partially monochromatic source
Perfectly polychromatic source
Only Red colour source
Atom+Photon --> Atom* . This represents
Emission
Spontaneous Emission
Stimulated Emission
Stimulated Absorption
Atom* --> Atom+Photon. This represents
Stimulated Absorption
Stimulated Emission
Spontaneous Emission
Induced absorption
Optical pumping is used in solid-state lasers such as
He-Ne laser
ruby lasers
CO2 laser
Argon laser
Conditions to achieve laser Emission
Active medium, Pumping source, optical resonator
Active medium, Pumping source, optical light
Xenon flash lamp, Pumping source, optical light
Active medium, Power, optical resonator
Which of the following is not pumping methods
Absorption pumping
Direct conversion pumping
Electric discharge pumping
Optical pumping
Which of the following is an example of optical pumping?
Carbon dioxide laser
Ruby laser
Excimer Laser
All the above
Example of an electric discharge pumping method
Nd:YAG Laser
Argon Laser
Ruby laser
None of the above
Which of the following is an example of a direct conversion pumping method?
Semiconductor Laser
Ruby laser
Argon Laser
None of the above
