1
WB JEE 2019
+1
-0.25
In Young's experiment for the interference of light, the separation between the slits is d and the distance of the screen from the slits is D. If D is increased by 0.5% and d is decreased by 0.3% then for the light of a given wavelength , which one of the following is true? "The fringe width ..............
A
increases by 0.8%
B
decreases by 0.8%
C
increases by 0.2%
D
decreases by 0.2%
2
WB JEE 2019
+1
-0.25
When the frequency of the light used is changed from $$4 \times {10^{14}}{s^{ - 1}}$$ to $$5 \times {10^{14}}{s^{ - 1}}$$, the angular width of the principal (central) maximum in a single slit Fraunhoffer diffraction pattern changes by 0.6 radian. What is the width of the slit (assume that the experiment is performed in vacuum)?
A
$$1.5 \times {10^{ - 7}}$$ m
B
$$3 \times {10^{ - 7}}$$ m
C
$$5 \times {10^{ - 7}}$$ m
D
$$6 \times {10^{ - 7}}$$ m
3
WB JEE 2018
+1
-0.25
If Young's double slit experiment is done with white light, which of the following statements will be true?
A
All the bright fringes will be coloured.
B
All the bright fringes will be white.
C
The central fringe will be white.
D
No stable interference pattern will be visible.
4
WB JEE 2017
+1
-0.25
Two monochromatic coherent light beams A and B have intensities L and $${{L \over 4}}$$, respectively. If these beams are superposed, the maximum and minimum intensities will be
A
$${{{9L} \over 4},{L \over 4}}$$
B
$${{{5L} \over 4}}$$ , 0
C
$${{{5L} \over 2}}$$ , 0
D
2L, $${{L \over 2}}$$
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