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M.C.Q (1 Marks)

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36 questions · timed · auto-graded

Question 21 Mark
The wavelength $\lambda$, frequency $v$, velocity $v$ and intensity I of a light ray transmitted in air respectively. If this ray enters water, then the values of these quantities become $\lambda^{\prime}, \nu^{\prime}, v^{\prime}$ and $I^{\prime}$ respectively. Which of the following relations is correct?
Answer
(B) - $v=v^{\prime}$
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Question 31 Mark
In case of linearly polarized light, the magnitude of the electric field vector :
Answer
(B) - Changes periodically with time
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Question 41 Mark
The wavelength of light used in an optical instrument is $\lambda_1=4000 Å$ and $\lambda_2=5000 Å$. The ratio of their corresponding resolution powers will be :
Answer
(D) - $5: 4$
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Question 51 Mark
When reflected light of intensity $I_0$ is incident on a polarizing sheet then the intensity of that light, which does not transmit is :
Answer
(B) - $\frac{1}{2} I _0$
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Question 61 Mark
What is the color of the interference fringe nearest to the central maximum in case the source light is white?
Answer
(D) - violet
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Question 71 Mark
Two coherent sources whose frequency ratio is $100: 1$ used to generate interference fringes. The ratio of maximum and minimum intensity in fringes will be :
Answer
(B) - $121: 81$
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Question 91 Mark
The central fringe obtained in the diffraction pattern of a single slit is :
Answer
(B) - of maximum intensity
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Question 121 Mark
For diffraction of light, it is necessary that the size of the obstacle in comparison to the wavelength of light waves will be :
Answer
(B) - almost equal
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Question 131 Mark
The angle of incidence of a ray of light on a transparent substance is $60^{\circ}$. The reflected ray is completely polarized. The refractive index of the material is :
Answer
(A) - $\frac{1}{\sqrt{2}}$
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Question 141 Mark
In the Fraunhofer diffraction experiment of single aperture, the condition of path difference ( $\Delta$ ) for the secondary maximum of $n^{\text {th }}$ order is :
Answer
(A) - $\Delta=(2 n+1) \lambda / 2$
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Question 151 Mark
In Young's double slit experiment, the wavelength is $6000 Å$, the screen is at a distance of 40 cm from the slits and the distance between the fringes is $0.012 cm $, then the separation between the slits will be :
Answer
(D) $2.0 mm$
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Question 161 Mark
The mean intensity in the interference pattern obtained from two coherent sources of equal intensity $I _0$ will be :
Answer
(C) - $4 I _0$
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Question 171 Mark
Distance between two slits $S_1$ and $S_2$ in Young's double slit experiment is 1 mm . What should be the width of each slit so that the $10^{\text {th }}$ maximum of the double slit is obtained at the central maximum of the slit?
Answer
(B) - 0.2 mm
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Question 181 Mark
Soap bubbles appear colored when seen in white light. The reason for this phenomenon is :
Answer
(B) - Interference.
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Question 191 Mark
In Young's double-slit experiments, a monochromatic light source is used. The shape of interference fringes produced on screen will be :
Answer
(C) - Hyperbola
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Question 201 Mark
In Young's double-slit experiment, the sodium lamp is replaced by a blue light lamp, then :
Answer
(D) - Fringe width will be reduced.
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Question 211 Mark
Two light waves of intensities I and 4I, makes fringes by interference. The phase difference between the waves at point A of the screen is $\pi / 2$ and at point B is $\pi$. Then at point A and B the difference between the resulting intensities is :
Answer
(B) - 4 I
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Question 221 Mark
The color of the bright fringe near the central white bright fringe obtained in the interference pattern produced by white light will be :
Answer
(D) - violet
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Question 231 Mark
Coherent sources of light produce constructive interference while there is a phase difference between them is :
Answer
(D) - $2 \pi$
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Question 241 Mark
The light source will be coherent if :
Answer
(A) - The phase difference remains fixed at their place of origin
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Question 251 Mark
The ratio of maximum and minimum intensities in an interference pattern is $25: 1$. The ratio of the intensities of the waves causing interference is-
Answer
(C) - $9: 4$
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Question 261 Mark
The displacement at point P by two light waves emitted from this light source is $Y _1=5 \sin \omega t$ and $Y _2$ $=3 \cos \omega t$ respectively, then both the waves will be :
Answer
(B) - Coherent.
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Question 281 Mark
On using white light in Young's double slit experiment:
Answer
(C) - Central fringe will be white but two-three colored fringes will appear black
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Question 291 Mark
Two waves are said to be coherent :
Answer
(D) - If between them phase difference should remain constant and the wavelength should be the same.
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Question 301 Mark
In Young's double slit experiment, at a fixed point where $\lambda$ is path difference $=\lambda / 6(\lambda=$ wavelength of the light used), the intensity is I. If $I _0$ is the maximum intensity then $I / I_0$ is equal to :
Answer
(A) - $\frac{3}{4}$
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Question 311 Mark
When a ray of light passes through a medium in which the velocity is low, then the values of its wavelength and frequency are respectively:
Answer
(B) - will decrease, unchanged
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Question 331 Mark
Two waves of same amplitude and same wavelength are superimposed in different phases. The amplitude of the resultant wave will be maximum when the phase difference between them is:
Answer
(A) - zero
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Question 341 Mark
In Huygens' theory, the plane of particles vibrating in the same state is called:
Answer
(A) - Wave front
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Question 351 Mark
Which of the following phenomena cannot be explained by the Huygens' wave theory?
Answer
(B) - Doppler effect
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M.C.Q (1 Marks) - Physics STD 12 Science Questions - Vidyadip