JEE Main 2020 (Online) 9th January Evening Slot | Ray & Wave Optics Question 147 | Physics

JEE Main 2020 (Online) 9th January Evening Slot

MCQ (Single Correct Answer)

-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]:

17%

34%

50%

21%

JEE Main 2020 (Online) 9th January Morning Slot

MCQ (Single Correct Answer)

-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 :

$${h \over {\sqrt 2 }}$$

$${h \over {3\sqrt 2 }}$$

$${3 \over 4}h\sqrt 2 $$

$${h \over {2\left( {\sqrt 2 + 1} \right)}}$$

JEE Main 2020 (Online) 9th January Morning Slot

MCQ (Single Correct Answer)

-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 :

20 m

200 m

600 m

60 m

JEE Main 2020 (Online) 8th January Evening Slot

MCQ (Single Correct Answer)

-1

In a double slit experiment, at a certain point on the screen the path difference between the two interfering waves is $${1 \over 8}$$th of a wavelength. The ratio of the intensity of light at that point to that at the centre of a bright fringe is :

0.853

0.568

0.672

0.760

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