JEE Main 2020 (Online) 2nd September Morning Slot | Ray & Wave Optics Question 145 | Physics

JEE Main 2020 (Online) 2nd September Morning Slot

MCQ (Single Correct Answer)

-1

Interference fringes are observed on a screen by illuminating two thin slits 1 mm apart with a light source ($$\lambda $$ = 632.8 nm). The distance between the screen and the slits is 100 cm. If a bright fringe is observed on a screen at a distance of 1.27 mm from the central bright fringe, then the path difference between the waves, which are reaching this point from the slits is close is

1.27 $$\mu $$m

2.05 $$\mu $$m

2.87 nm

2 nm

JEE Main 2020 (Online) 2nd September Morning Slot

MCQ (Single Correct Answer)

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JEE Main 2020 (Online) 2nd September Morning Slot Physics - Ray & Wave Optics Question 144 English

A spherical mirror is obtained as shown in the figure from a hollow glass sphere. If an object is positioned in front of the mirror, what will be the nature and magnification of the image of the object?
(Figure drawn as schematic and not to scale)

Inverted, real and unmagnified

Inverted, real and magnified

Erect, virtual and magnified

Erect, virtual and unmagnified

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 :

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

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

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

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

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