Part A: Multiple choice questions. Answer all the questions
1. A large lens having two spherical
surfaces separated by a distance, which is not negligible in comparison to the
radii of curvature of the spherical surfaces is known as
A) Telescope B)
Thin lens C) Thick lens D) None of these
2. Important characteristic of
laser beam is
A) Interference B)
Diffraction C) Dispersion D) Coherence
3. Deviation produced by a small
angled prism is
A) A(n-1) B) A(1-n) C)
2A D) None of these.
4. Which of the following is not
an example of reflecting prism
A) Biprism B) Dove prism C) Penta prism D) Porro prism
5. The light passing through an
instrument is limited in cross-section either by the finite diameter or
diaphragms which are known as
A) Valves B) Stops C)
Antennas D) Objectives
6. In Ramsden eyepiece, two
plano-convex lenses each of focal length ‘f’ is separated by a distance equal
to
A) f B)
2f C) 
D) 
f
D) f
7. The ratio of focal lengths of
two lenses which constitutes an Huygens eyepiece is
A) 1:1 B)
3:1 C) 3:2 C) 1:4
8. Emission of a photon by an
excited atom due to interaction of external energy is called
A) Spontaneous emission B)
Stimulated emission
C) Induced absorption D) Light amplification
9. Snell’s law is given by,
A) n = 
B) n = 
C)
n = tan i D) None of
these
B) n = C)
n = tan i D) None of
these
10. The life time of an atom at
the ordinary excited state is of the order of
A) few milli second B) few
nano second C) few micro second D) Unlimited
11. Rate of induced absorption
depends on
A) number of atoms in the lower
energy state B) the energy
density
C) number of atoms in the higher
energy state D) Both A and B
12. The point of intersection of
the first principal plane with the principal axis is called as
A) First focal point B) Second focal point
C) Second principal point D) First principal point
13. Emission of electrons from a
metal surface when light is incident on it is called as
A) Spontaneous emission B) Thermionic emission
C) Field emission D) Photoelectric
emission
14. Optical fiber is a
A) Waveguide B) Signal generator C) Amplifier D) None of these
A) Waveguide B) Signal generator C) Amplifier D) None of these
15. Which
one of the following is an attenuation mechanism?
A) Absorption B)
Scattering
C) Microscopic and macroscopic bending D) All of these (15×1Mark)
Part B: Answer any one question
16. State Fermat’s principle and
apply the same to prove the laws of refraction of light.
17. Explain the different types
of optical fibers. (1×10
Marks)
Part C: Answer any 5 questions
18. Distinguish between aperture
stop and field stop.
19. Compare the merits and
demerits of Ramsden eyepiece and Huygens eyepiece.
20. Write a note on achromatic
combination of prisms where ray of light pass through without deviation
suffering dispersion.
21. What is spherical aberration?
Mention some methods to reduce spherical aberration.
22. With the help of a neat
figure, explain the working of a simple telescope.
23. The refractive indices of
core and cladding are 1.50 and 1.48 respectively in an optical fiber. Find the
numerical aperture and angle of acceptance.
24. Discuss the possible ways
through which radiation and matter interaction takes place.
(5×5
Marks)
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