29th October - Ray Optics Contact Number: 9667591930 / 8527521718

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1.

A spherical fishbowl of radius 15 cm is filled with water of refractive index $\frac{4}{3}$. A cat standing outside in air at a distance of 30 cm from the centra of fishbowl is looking at the fish. At what distance from the centre, would the cat appear to fish situated at the centre?

1. 45 cm

2. 30 cm

3. 15 cm

4. 25 cm

2.

A boy with defective eye-sight cannot see things beyond 50cm. The corrective lens required has the power

1. +1D

2. +2D

3. -1D

4. -2D

3.

Two objects are placed at a distance of 100 m from a person. The diameter of the eye-lens of the person is 2 mm. What should be the separation between the objects so that they can be seen just resolved? (The wavelength of light is 5000 $\stackrel{o}{A}$)

1. 1 cm

2. 1.5 cm

3. 2 cm

4. 3 cm

4.

Refractive index of material of an equilateral prism is $\sqrt{2}$. Angle of incidence for minimum deviation is

1. ${60}^{\xb0}$

2. $45\xb0$

3. $30\xb0$

4. $15\xb0$

5.

The near point of a hypermetropic eye is 1m. What is the power of the lens required to correct this defect?

(1) -3 D

(2) +3 D

(3) +1 D

(4) -1.75 D

6.

The following diagram shows a glass sphere of radius 10 cm with a paraxial incident ray. The refractive index of the material of the glass is

1. 2

2. 1.5

3. 1.75

4. 1.3

7.

A convex lens forms the image of the point object O on the screen. If a glass slab of thickness 3 cm and refractive index 1.5 is put as shown below, then to have the image of the object on the screen the object should be shifted

(1) Away from the lens by 1 cm

(2) Away from the lens by 1.5 cm

(3) Towards the lens by 1 cm

(4) Towards the lens by 1.5 cm

8.

The focal length of a convex lens is 40 cm and the size of the inverted image formed is half of the object. The object distance is

(1) 60 cm

(2) 120 cm

(3) 30 cm

(4) 180 cm

9.

A plane mirror is fixed in YZ-plane at x = 0. The velocity of a moving object is $\overrightarrow{{v}_{0}}=3\hat{i}+6\hat{j}+4\hat{k}$. The velocity of the image relative to a stationary observer will be:

1. $3\hat{i}-6\hat{j}-4\hat{k}$

2. $3\hat{i}-6\hat{j}+4\hat{k}$

3. $-3\hat{i}+6\hat{j}+4\hat{k}$

4. $-3\hat{i}-6\hat{j}-4\hat{k}$

10.

Three identical thin convex lenses are kept as shown in the figure. A ray passing through the lenses is shown. The focal length of each lens is

1. 5 cm

2. 10 cm

3. 15 cm

4. 20 cm

11.

If light ray is incident normally on face AB of a part of a prism, then for no emergent ray from second face AC [$\mu \to $refractive index of glass of prism]

(1) $\mu =\frac{2}{\sqrt{3}}$

(2) $\mu >\frac{2}{\sqrt{3}}$

(3) $\mu <\frac{2}{\sqrt{3}}$

(4) $\mu $ can have any value

12.

Assertion: The nature of the image of an object depends on the size of the mirror.

Reason: It is not possible to obtain a real image by a plane mirror.

(1) Both Assertion and Reason are true and the reason is the correct explanation of the assertion.

(2) Both Assertion and Reason are true but the reason is not the correct explanation of the assertion.

(3) Assertion is a true statement but Reason is false.

(4) Both Assertion and Reason are false statements.

13.

The focal length of an equiconvex glass lens(${\mu}_{glass}=1.5$) in air is 20 cm. The relative refractive index of glass with respect to water is $\frac{9}{8}$. If the lens is dipped in water, then its new focal length in water is-

1. 20 cm

2. -20 cm

3. 80 cm

4. -80 cm

14.

Two convex lenses of focal length X and Y are placed parallel to each other. An object at infinity from the first lens forms its image at infinity from the second lens. The separation between the two lenses should be:

1. X + Y

2. $\frac{X+Y}{2}$

3. X - Y

4. $\frac{X-Y}{2}$

15.

A light beam containing red, yellow and blue color, falls on the interface of glass-air as

shown. If the yellow light is just totally internally reflected then emergent ray in air contain

1. Both red and blue color

2. Only red color

3. Only blue color

4. No color

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