1
JEE Main 2020 (Online) 9th January Evening Slot
+4
-1
There is a small source of light at some depth below the surface of water (refractive index = $${4 \over 3}$$) in a tank of large cross sectional surface area. Neglecting any reflection from the bottom and absorption by water, percentage of light that emerges out of surface is (nearly) :
[Use the fact that surface area of a spherical cap of height h and radius of curvature r is 2$$\pi$$rh]:
A
17%
B
34%
C
50%
D
21%
2
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
A vessel of depth 2h is half filled with a liquid of refractive index $$2\sqrt 2$$ and the upper half with another liquid of refractive index $$\sqrt 2$$ . The liquids are immiscible. The apparent depth of the inner surface of the bottom of vessel will be :
A
$${h \over {\sqrt 2 }}$$
B
$${h \over {3\sqrt 2 }}$$
C
$${3 \over 4}h\sqrt 2$$
D
$${h \over {2\left( {\sqrt 2 + 1} \right)}}$$
3
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
The aperture diameter of a telescope is 5m. The separation between the moon and the earth is 4 × 105 km. With light of wavelength of 5500 $$\mathop A\limits^o$$, the minimum separation between objects on the surface of moon, so that they are just resolved, is close to :
A
20 m
B
200 m
C
600 m
D
60 m
4
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
An object is gradually moving away from the focal point of a concave mirror along the axis of the mirror. The graphical representation of the magnitude of linear magnification (m) versus distance of the object from the mirror (x) is correctly given by :
(Graphs are drawn schematically and are not to scale)
A
B
C
D
EXAM MAP
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