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Physics Lab Viva Voce Questions and its answers Laser Parameters
1. What is semi conductor diode laser?
Semiconductor diode laser is a specially fabricated pn junction diode. It emits laser light when it is
forward biased.
2. What is LASER?
The term LASER stands for Light Amplification by Stimulated Emission of Radiation. It is a device
which produces a powerful, monochromatic collimated beam of light in which the waves are coherent.
3. What are the characteristic of laser radiation?
Laser radiations have high intensity, high coherence, high monochoromation and high directionality
with less divergence.
AIR WEDGE
1.What is meant by interference of light?
When the two waves superimpose over each other, resultant intensity is modified. The modification in
the distribution of intensity in the region of superposition is called interference.
2.Is there is any energy loss in interference phenomenon?
No, there is only redistribution of energy ie, energy from dark places is shifted to bright places
3.What are interference fringes?
They are alternately bright and dark patches of light obtained in the region of superposition of two wave
trains of light.
SPECTROMETER GRATING
1.what is plane transmission diffraction grating?
A plane transmission diffraction grating is an optically plane parallel glass plate on which equidistant,
extremely close grooves are made by ruling with a diamond point.
2. In our experiment. What class of diffraction does occur and how?
Fraunhofer class of diffraction occurs. Since the spectrometer is focused for parallel rays, the source
and the image are effectively at infinite distances from the grating.
3. How are the commercial gratings are made?
A commercial gratings is made by pouring properly diluted cellulose acetate on the actual grating and
drying it to a thin strong film. The film is detached from the original grating and is mounted between
two glass plates. A commercial grating is called replica grating. In our experiment we use plane type
replica grating.
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PHYSICS PRACTICALS VIVA QUESTIONS
1. NEWTON S RINGS
1) Explain interference?
The phenomenon in which alternate bright and dark bands are observed due to the superposition of light waves proceeding from two coherent sources of light is known as interference.
2) What are coherent sources?
Two sources are said to be coherent if they emit light waves of the same wavelength and start with same phase or have a constant phase difference.
3) Write the relation between path difference and phase difference?
4) By what method coherent sources are derived in the case of Newton s rings?
The rays are derived from the same incident ray by the division of amplitude and therefore are coherent.
5) Explain fringes of equal optical thickness.
The occurrence of fringes of equal thickness is due to interference of light reflected from the front and rear boundaries of the film (fringes of equal thickness in reflected light) or of light transmitted directly through the film and light twice reflected at its boundaries (fringes of equal thickness in transmitted light).
6) Explain fringes of equal chromatic order.
Fringes which have same chromatic properties are called fringes of equal chromatic order.
7) Write the condition for maxima and minima.
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Abstract
The air-wedge shearing interferometer is probably the simplest type of interferometer designed to visualize the disturbance of the wavefront after propagation through a test object. This interferometer is based on utilizing a thin wedged air-gap between two optical glass surfaces and can be used with virtually any light source, even with non-coherent white light.
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Hi am sai nikhil I would like to get details on air wedge experiment viva questions with answers pdf ..My friend Justin said air wedge experiment viva questions with answers pdf will be available here and now i am living at bangalore and i last studied in the college/school naraya and now am doing engineering can u please help me out thanks in advance
