1
JEE Main 2022 (Online) 28th July Morning Shift
+4
-1

In normal adujstment, for a refracting telescope, the distance between objective and eye piece is $$30 \mathrm{~cm}$$. The focal length of the objective, when the angular magnification of the telescope is 2 , will be :

A
20 cm
B
30 cm
C
10 cm
D
15 cm
2
JEE Main 2022 (Online) 27th July Morning Shift
+4
-1

A microscope was initially placed in air (refractive index 1). It is then immersed in oil (refractive index 2). For a light whose wavelength in air is $$\lambda$$, calculate the change of microscope's resolving power due to oil and choose the correct option.

A
Resolving power will be $$\frac{1}{4}$$ in the oil than it was in the air.
B
Resolving power will be twice in the oil than it was in the air.
C
Resolving power will be four times in the oil than it was in the air.
D
Resolving power will be $$\frac{1}{2}$$ in the oil than it was in the air.
3
JEE Main 2022 (Online) 26th July Evening Shift
+4
-1

Light travels in two media $$M_{1}$$ and $$M_{2}$$ with speeds $$1.5 \times 10^{8} \mathrm{~ms}^{-1}$$ and $$2.0 \times 10^{8} \mathrm{~ms}^{-1}$$ respectively. The critical angle between them is :

A
$$\tan ^{-1}\left(\frac{3}{\sqrt{7}}\right)$$
B
$$\tan ^{-1}\left(\frac{2}{3}\right)$$
C
$$\cos ^{-1}\left(\frac{3}{4}\right)$$
D
$$\sin ^{-1}\left(\frac{2}{3}\right)$$
4
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

For an object placed at a distance 2.4 m from a lens, a sharp focused image is observed on a screen placed at a distance 12 cm from the lens. A glass plate of refractive index 1.5 and thickness 1 cm is introduced between lens and screen such that the glass plate plane faces parallel to the screen. By what distance should the object be shifted so that a sharp focused image is observed again on the screen?

A
0.8 m
B
3.2 m
C
1.2 m
D
5.6 m
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