Chap.9 Physical optics MCQs with solution
Physical
optics
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1)
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The
locus of all points in a medium having the same phase of vibration is called a) Crest b) Trough c) Wavelength d) Wave front |
D |
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2)
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The
distance between two consecutive wave fronts is called: a) Time period b) Frequency c) Wavelength d) Displacement |
c |
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3)
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Which
one of the following is nearly monochromatic light? a) Light form fluorescent tube b) Light form sodium lamp c) Light form neon lamp d) Light form simple lamp |
B |
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4)
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Two
sources of light are coherent if they emit rays of a) Same wavelength b) Same amplitude of vibration c) Same wave length with constant phase difference d) Same amplitude and wavelength |
C |
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5)
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Sodium
chloride in a flame gives out pure: a) Blue light b) Yellow light c) Red light d) White light |
B |
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6)
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When
crest of one wave falls over the trough of the other wave, this phenomenon is known as a) Polarization b) Constructive interference c) Destructive interference d) Diffraction |
B |
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7)
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The
condition for constructive interference of two coherent beams is that the path difference should be a) Integral multiple of λ/2 b) Integral multiple of λ c) Odd Integral multiple of λ/2 d) Even integral multiple of λ |
B |
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8)
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The
condition for destructive interference of two coherent beams is that the path difference should be a) Integral multiple of λ/2 b) Integral multiple of λ c) Odd Integral multiple of λ/2 d) Even integral multiple of λ |
C |
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9)
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In
Young’s double slit experiment, the distance between two adjacent bright fringes, ∆𝑦
is: b) 2λL/d b) 3λL/d c) λL/2d d)
λL/d |
D |
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10) |
In
Young double slit experiment, if white light is used a) Alternate dark and bright fringes will
be seen b) Colored fringes will be seen c) No interference fringes will be seen d) Impossible to predict |
c |
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11) |
The
center of Newton’s rings is_________ due to destructive interference: a) Bright b) Dark c) Colorless d) Red |
B |
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12) |
When
the Newton’s rings are observed with reflected light, the central spot is: a) Red b) Blue c) Dark d) Bright |
C |
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13) |
When
the Newton’s rings are observed with transmitted light, the central spot is: a) Red b) Blue c) Dark d) Bright |
D |
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14) |
The
appearance of Color in thin films is due to a) Diffraction b) Dispersion c) Interference d) Polarization |
C |
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15) |
Soap
film exhibit brilliant colors in sun light due to: a) Dispersion of light b) Interference of light c) Diffraction of light d) Scattering of light |
B |
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16) |
A
light ray traveling form rarer to denser medium suffers a phase change of: a) 60° b) 90° c) 180° d) 45° |
C |
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17) |
A
light ray traveling form denser to rarer medium suffers a phase change of: a) 0° b) 90° c) 180° d) 45° |
A |
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18) |
One
angstrom is equal to: a) 10−9 𝑚 b) 10−8 𝑚 c) 10−10 𝑚 d) 10−11 𝑚 |
c |
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19) |
2𝑑 sin 𝜃 = 𝑚𝜆 is called: a) Laplace’s equaiton b) Reflection equation c) Refraction equaion d) Bragg’s equation |
D |
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20) |
𝑑 sin 𝜃 = 𝑚𝜆 is called: a) Laplace’s equaiton b)
Slit Diffraction Condition c) Refraction equaion d) Bragg’s equation |
B |
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21) |
Bending
of light around the edges of an obstacle is known as: a) Refraction b) Polarization c) Diffraction d) Interference |
C |
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22) |
The
bending of a beam of light when it passes from one medium to another is known as: a) Refraction b) Reflection c) Diffraction d) Dispersion |
A |
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23) |
The
effective path difference between two reflected beams, in x-ray diffraction by crystal is: b) dsinθ b) 2dsinθ c) disn θ/2 d)
dsin2θ |
B |
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24) |
The
equation of Michelson’s interferometer is: b) L = c) L =mλ d)
L = 2mλ |
A |
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25) |
Coloured
fringes observed in soap bubbles are the example of: A.Diffraction
B.Interference C.Reflection
D.Refraction |
B |
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26) |
Monochromatic
green light of wave length 5 x 10-7 m illuminates a pair of silts
1mm apart the separation of bright lines on the interference pattern formed
on a screen 2m away is: A. 0.25m B. 0.1mm C. 1.0mm D. 0.0lm |
C |
Y= λd/d |
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27) |
Two wave
sources are oscillating in phase.Each source produces a wave of wavelength λ.
The two waves from the sources meet at point X with a phase difference of
90°. What is a possible difference in the distances from two wave sources to
point X? A) λ/8 B) λ/4 C) λ/2 D) λ |
B |
Here Phase
difference =900 and p
= 1800 path
difference = phase difference x λ /2p
= 90 x λ/2 x 1800 = λ/4 |
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28) |
A
diffraction grating is used to measure the wavelength of monochromatic light,
as shown in the diagram The spacing
of the slits in the grating is 1.00 x 10-6 m. The angle between
the first order diffraction maxima is 60.0° What is the wavelength of the
light? A)287 nm B)470 nm C)574 nm D)940 nm. |
C |
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29) |
In Young
double slit experiment with sodium light, the slit are 0.589 m apart. What is
the angular Width of the third maximum given
λ=589nm: A.sin-1
(3x10-6) B.
sin-1 (3x10-8) C. sin-1
(3x10-6) D.
sin-1 (3x10-8) |
A |
: dsinθ=mλ Θ= sin-1
mλ/d=sin-1 3 x 589 x 10-9
/0.589 = sin-1 (3x10-6) |
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30) |
When the
light form two lamps falls on a screen, no interference pattern can be
obtained. Why is this? A)The lamps
are not point sources B)The lamps
emit light of different amplitudes. C)The light
from the lamps is not coherent D)The light
form the lamps is white. |
c |
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31) |
Two
coherent monochromatic sets of waves will interfere constructively in the
region of superposition only if the path difference between them is: (a)Half
wavelength (b)Integral
number of wavelength (c) Quarter
wavelength (d)Odd
integral number of half wavelength |
B |
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