1
JEE Main 2021 (Online) 25th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 $$\mu$$m. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that:
A
its size increases, but intensity decreases
B
its size increases, and intensity increases
C
its size decreases, but intensity increases
D
its sizes decreases, and intensity decreases
2
JEE Main 2021 (Online) 25th February Morning Slot
MCQ (Single Correct Answer)
+4
-1
Two coherent light sources having intensity in the ratio 2x produce an interference pattern. The ratio $${{{I_{\max }} - {I_{\min }}} \over {{I_{\max }} + {I_{\min }}}}$$ will be :
A
$${{2\sqrt {2x} } \over {2x + 1}}$$
B
$${{2\sqrt {2x} } \over {x + 1}}$$
C
$${{\sqrt {2x} } \over {x + 1}}$$
D
$${{\sqrt {2x} } \over {2x + 1}}$$
3
JEE Main 2021 (Online) 24th February Evening Slot
MCQ (Single Correct Answer)
+4
-1
If the source of light used in a Young's double slit experiment is changed from red to violet :
A
the fringes will become brighter.
B
the intensity of minima will increase.
C
consecutive fringe lines will come closer.
D
the central bright fringe will become a dark fringe.
4
JEE Main 2021 (Online) 24th February Morning Slot
MCQ (Single Correct Answer)
+4
-1
The focal length f is related to the radius of curvature r of the spherical convex mirror by :
A
f = r
B
f = $$-$$ r
C
f = +$${{1 \over 2}}$$ r
D
f = $$-$$$${{1 \over 2}}$$ r
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