Transcript Physic

Ques 1 :
i)Two different parts of monochromatic light act as coherent sources.
ii) Two different monochromatic sources act as coherent sources.
iii) Two different part of same wave front act as coherent sources
iv) Two images of same source act as coherent sources
a) i) & ii
b) ii) & iii)
c) iii) & iv)
d) ii) & iv)
Ans 1:
c)
iii) Two different part of same wave
front act as coherent sources
iv) Two images of same source act
as coherent sources
Ques 2 :
Pairs of sources of light that can act as coherent sources are
a) Two images of same source
b) One source and its image
c) Two different parts of same wave front
d) All of the above
Ans -2:
d) All of the above
Ques 3 :
In interference
a) Energy is created at Maxima.
b) Energy is destroyed at minima.
c) Energy is redistributed from minima to maxima without the
movement of medium from minima to maxima .
d) Energy is redistributed by movement of the medium from minima
to maxima
Ans 3:
c)
Energy is redistributed from minima
to maxima without the movement
of medium from minima to maxima
Ques 4 :
When two coherent sources of light interfere
a) Maxima is obtained where phase difference is odd multiple of π
b) Maxima is obtained where phase difference is even multiple of π
c) Minima is obtained where phase difference is even multiple of π
d) None of the above
Ans 4:
b) Maxima is obtained where phase
difference is even multiple of π
Ques 5 :
In Huygens's Double slit experiment the valid
equation at minima is
a) Path difference = (2n-1)λ/2
b) Path difference = (2n+1)λ/2
c) Path difference = (2n-1)λ
d) Path difference = (2n+1)λ
Ans 5 :
a) Path difference = (2n-1)λ/2
Ques 6 :
Intensities of successive maximas due to diffraction
from single slit are in the ratio of
a) 1: 1/22: 1/64 : 1/122 …..
b) 1 : 1 : 1: ……
c) 1: 22 : 64 : 122 …..
d) 1 : 2 : 4 : 8 ………
Ans 6 :
a) 1: 1/22: 1/64 : 1/122 …..
Ques 7 :
Diffraction is the phenomenon of bending of light
a) While passing from one medium to another
b) From sharp edges into geometric shadow.
c) From sharp edges into geometric image
d) From sharp edges into geometric image or shadow.
Ans 7:
d) From sharp edges into geometric image or shadow.
Ques 8 :
In diffraction from N no of parallel slits there are …….. Secondary
minima and …….. Secondary maxima between two successive principal
maxima
a) N+1, N+2
b) N, N-1
c) N-1 , N-2
d) N-2, N-1
Ans 8:
c) N-1 , N-2
Ques. 9 :
Maximum order n of spectrum that can be observed with
diffraction grating of grating element (a+b) is given by
a) n ≤ λ (a + b)
b) n ≤ λ /(a + b)
c) n ≥ λ /(a + b)
d) n ≤ (a + b) / λ
Ans 9:
d) n ≤ (a + b) / λ
Ques. 10 :
Hazarduous effect of laser is the most on
a) Skin
b) Eyes
c) Heart
d) Blood
Ans 10:
b) Eyes
Ques 11 :
If widths of transparency and opacity are equal then missing
order of spectra are
a) 2, 4, 6, 8 …………..
b) 1, 5, 9, 13 ….
c) 3, 6, 9, ………………..
d) 1, 3 , 5 , 7,
Ans 11:
a) 2, 4, 6, 8 …………..
Ques 12 :
For two objects to be just resolved first minima of one should fall
on central maxima of other. This statement was given by
a) Einstein.
b) Michelson and Morley.
c) Rayleigh.
d) Newton
Ans 12:
c) Rayleigh.
Ques 13
What would the mass of a 9.11 X 10-31 kg electron be if it were to travel
at c?
a) Infinite
b) 9.11 x 10-31 Kg
c) 1.6 x 10-12 Kg
d) Zero
Ans 13:
a) Infinity
Ques 14:
An observer on a spacecraft moving directly away from the sun is
moving at a speed of 0.3 c will find that the light waves pass by him
(from behind) at a relative speed of .
a) 1.3 c
b) c
c) 0.7 c
d) 0.9c
Ans 14:
b) c
Ques 15:
Which experiment was the first compelling evidence in favour of time
dilation?
a) Muon decay
b) The Michelson-Morley interferometer
c) Rutherford's Alpha Scattering
d) Young's double-slit
Ans 15 :
a) Muon decay
Ques 16:
Evidence for conversion of mass into energy and vice versa are
a) Nuclear reactor and pair production
b) Pair production and Nuclear reactors.
c) Hydrogen bomb and atom bomb
d) Energy from Sun and Stars
Ans16 :
a) Nuclear reactor and pair production
Ques 17 :
Kinetic Energy of a relativistic particle is twice its rest mass energy.
a) Moving mass is two times its rest mass
b) Moving mass is half of its rest mass.
c) Moving mass is three times the rest mass
d) Moving and rest mass are always same.
Ans 17:
c) Moving mass is three times the rest mass
Ques 18 :
What is the minimum no of energy levels needed for lasing?
a) 1
b) 4
c) 2
d) 3
Ans 18:
d) 3
Ques 19 :
When electrons drops down from a higher energy state and recombine
with hole what is produced?
a) Gamma ray.
b) Phonon.
c) Photon.
d) Current.
Ans 19 :
c) Photon.
Ques 20 :
What particle play major role in the process of lasing.
a)Neutron
b) Proton.
c) Electron.
d) Krypton.
Ans 20 :

c) Electron.
Ques 21:
Basic difference between three and four level laser is that
a) Four level is independent of pumping rate
b) Three level is independent of pumping rate
c) Four level is independent of pumping power
d) Three level is independent of pumping power
Ans 21 :
a) Four level is independent of pumping rate
Ques 22:
If a wave can be polarised it must be:
a) Electromagnetic Wave
b) Longitudinal Wave
c) Seismic wave
d) Transverse wave
Ans 22 :
d) Transverse wave
Question 23
The relation between Brewster angle λ and critical angle C is
a)
b)
c)
d)
(sin C) -1 = tan λ
Sin C = tan λ
C=λ
C = 1/ λ
Ans. 23
a) (sin C)
-1
= tan λ
Ques. 24
The wave fronts of Ordinary and Extra-ordinary waves in a
crystal are shown in figure. The crystal is
a) –ve crystal
b) +ve crystal
c) Neutral
Ans. 24
b) +ve crystal
Ques. 25
The wave fronts of Ordinary and Extra-ordinary waves in a
crystal are shown in figure.
a)
b)
c)
d)
Spherial wave front is for O-ray
Elliptical wave front is for O-ray
Spherial wave front is for E-ray
Straight line is for E-ray
Ans. 25
a) Spherial wave front is for O-ray
Ques. 26
Read Following Statements
1. Optic axis is a line equally inclined to all edges meeting at
blunt corners and any line parallel to it is also an optic axis.
2. Velocities of O-ray and E-ray are same in along optic axis
a)Only statement 1 is correct.
b)Only statement 2 is correct
c) Both the statements 1 & 2 are correct
d)Statement 1 is correct but statement 2 is
not correct
Ans. 26
c) Both the statements 1 & 2 are correct
Ques. 27
1. Elliptically polarised light is produced when O-ray and E-ray
having equal amplitude superimpose over each other and
have a path difference of l/4
2. Circularly polarised light is produced when O-ray and E-ray
having equal amplitude superimpose over each other and
have a path difference of l/4
a) statement 1 is correct.
b) statement 2 is correct
c) Both the statements 1 & 2 are correct
d) None of the above statement are correct
Ans. 27
b) Statement 2 is correct
Ques. 28
Nicol Prism
a)Acts as Polariser and can be used to produce
only plane polarised light.
b)Acts as Polariser and produces only circulary
polarised light.
c) Acts as only analyser and produces plane
polarised light.
d) Can act both as polariser and analyser.
Ans. 28
d) Can act both as polariser and analyser.
Ques. 29
You send a traveling wave along a particular string by oscillating the string. On
increasing the frequency of oscillation
i)
The Speed of wave increases
ii) Wavelength of wave decreases without any change of speed
If instead of increasing frequency tension in string is increased
iii) Speed of wave decreases
iv) Wave length of wave increases
a) i) and ii) are correct.
b) ii) and iii) are correct
c) iii) and iv) are correct
d) i) and iv) are correct
Ans. 29
d) i) The Speed of wave increases and iv)
Wave length of wave increases
are correct
Ques. 30
a)Optical Path and Geometric path are
same.
b)Geometric path is always larger than
path.
c) Geometric path is always less than
path.
d) Geometric path is always larger than
path in Transparent medium.
always
optical
optical
optical
Ans. 30
d) Geometric path is always larger than optical path
in Transparent medium.
Ques. 31
According to Einstein postulates of theory of relativity
i) Laws of physical phenomenon are same in all Non inertial frames
of reference
ii) Velocity of light is independent of motion of source and observer
iii) Laws of physical phenomenon are same in all inertial frames of
reference
iv) Velocity of light is independent of motion of source but depends
upon motion of observer
a) ii) and iii) are correct.
b) i) and ii) are correct.
c) i) and iv) are correct.
d) ii) and iv are correct.
Ans. 31
a) ii) Velocity of light is independent of
motion of source and observer and iii)
Laws of physical phenomenon are same in
all inertial frames of reference
are correct.
Ques. 32
a) In diffraction all fringes are of unequal width
and in interference all fringes are of equal
width.
b) In diffraction all fringes are of equal width and
in interference all fringes are of unequal width.
c) In diffraction as well interference intensities of
all fringes are equal.
d) Diffraction and refraction both show that light
is transverse in nature
Ans. 32
a) In diffraction all fringes are of unequal
width and in interference all fringes are
of equal width.
Ques. 33
If n is the order of spectrum and N is Resolving power of
grating is given by
• N/n
• Nxn
• n/N
d) l x dl
Ans. 33
b) N x n
Ques. 34
In relativistic Mechanics energy E and momentum p are
related by equation
• E2 = p2 c2 + mo2 c4
• E2 = p2 c2 + mo2 c2
• E = p2/2m
d) p = (2mE)1/2
Ans. 34
a) E2 = p2 c2 + mo2 c4
Ques. 35
If a thin transparent sheet of refractive index m is
introduced in the path of one of the interfering beams
the shift in the fringes is given by
a)
b)
c)
d (   1)t
D
D (   1)t
d
D
d (   1)t
Ans. 35
a)
d (   1)t
D