R4RIN – MCQs, Mock Tests | NCERT Class 12 MCQ Questions for Class 12 Physics Chapter 9 Ray Optics and Optical Instruments

Which of-the following is not a property of light?

1. It can travel through vacuum
2. It has a finite speed
3. It requires a material medium for its propagation
4. It involve transportation energy

✅ Correct Answer: 3

Two points P and q are situated at the same distance from a source of light but on opposite sides. The plane difference between the light waves passing through P and q will be:

1. n
2. 2n
3. π/2
4. zero

✅ Correct Answer: 4

The phase difference between the electric and the magnetic field vectors in electromagnetic waves is

1. π/4
2. π/2
3. π
4. Zero

✅ Correct Answer: 4

A ray of light travelling in air is incident of a glass slab. The ray gets partly reflected and partly refracted. The phase difference between the reflected and the refracted waves is :

1. π/2
2. π/4
3. π
4. Zero

✅ Correct Answer: 3

Which of the following cannot be polarised?

1. radiowaves
2. transverse waves
3. sound waves
4. X rays

✅ Correct Answer: 3

If a mirror is approaching you at a speed of 10 ms^1, the speed with which your image approach you is:

1. 10 ms-1
2. 5 ms-1
3. 20 ms-1
4. 15 ms-1

✅ Correct Answer: 3

The refractive indices (R.I.) of glass and water with respect to air are 3/2 and 4/3 respectively. The R.I. of glass w.r. to w ater is:

1. 8/9
2. 9/8
3. 7/6
4. 2

✅ Correct Answer: 2

The angle of minimum deviation for an equilateral glass prism is 30°. Refractive index of the prism is:

1. 1√3
2. √2
3. 1
4. can’t be determined

✅ Correct Answer: 2

A beam of light is incident at 60° to a plane surface. The reflected and refracted rays are perpendicular to each other. What is the R.I. of the surface:

1. 1√3
2. √3
3. 1/3
4. 3

✅ Correct Answer: 2

A convergent lens will become less convergent in :

1. oil
2. water
3. both of (a) and (b)
4. None of the above

✅ Correct Answer: 2

A thin glass (RI = 32) lens has optical power of – 5D in air. Its optical power in a liquid medium with RI = 1.6 will be:

1. -2.5 D
2. 25 D
3. -ID
4. 0.625 D

✅ Correct Answer: 4

On reflection from a denser medium, a light wave suffers a phase difference of:

1. π
2. π/2
3. π/4
4. 2π

✅ Correct Answer: 1

The branch of optics dealing with the formation of images using the concept of straight line propagation of light is called:

1. geometrical optics
2. physical optics
3. corpuscular optics
4. quantum optics

✅ Correct Answer: 4

When light travels from one medium to another, which of the following does not change?

1. frequency
2. refractive index
3. velocity
4. wavelength

✅ Correct Answer: 1

Two lens of power -15 D and +5 D are placed in contact co-axially. The focal length of equivalent lens is:

1. -10 cm
2. -20 cm
3. +10 cm
4. None

✅ Correct Answer: 1

The air bubble inside water shine due to:

1. Reflection
2. Refraction
3. T.l.R.
4. None of the above

✅ Correct Answer: 3

When a ray of light (white) enters a lens, undergoes a change is:

1. wavelength
2. velocity
3. frequency
4. both velocity and wavelength

✅ Correct Answer: 4

Radio waves from an antenna travel with the velocity of:

1. light
2. sound
3. ultrasonics
4. supersonics

✅ Correct Answer: 1

A point object is placed at the centre of a glass sphere of radius 6 cm 3 and RI = 32. The distance of virtual image from the surface of the sphere is :

1. 2 cm
2. 4 cm
3. 6 cm
4. 12 cm

✅ Correct Answer: 2

The RI. of the material of a prism is √2 and its refracting angle is 30°. One of the refracting surface of the prism is made a mirror. A beam of monochromatic light entering the prism from the other face retraces its path, after reflection from mirror surface. The angle of incidence on prism is:

1. 0°
2. 30°
3. 45°
4. 60°

✅ Correct Answer: 3

A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when seen in the light of mean λ = 5000 A is of the order of:

1. 5 mm
2. 5 cm
3. 0.5 m
4. 5 m

✅ Correct Answer: 1

When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is :

1. polarized
2. of longer λ
3. of shorter λ
4. of high intensity

✅ Correct Answer: 3

A convex lens is dipped in a liquid, whose R.I. is equal to that of R.I. of material of the lens. Then its focal length will:

1. become zero
2. become infinite
3. reduce
4. increase

✅ Correct Answer: 2

Which of the following is not essential for the formation of a pure spectrum?

1. parallel beam of light
2. narrow beam of light
3. screen
4. prism in the minimum deviation position

✅ Correct Answer: 3

A certain far-sighted person cannot see objects closer to the eye than 100 cm. The power of the lens which will enable him to read at a distance of 25 cm will be?

1. 3D
2. 1D
3. 4D
4. 2D

✅ Correct Answer: 1

Which produces additional luminiscence in a fluorescent tube?

1. infra red rays
2. ultraviolet rays
3. micro waves
4. radio waves

✅ Correct Answer: 2

ar point of a myopic eye is 40 cm. The dioptic power of a corrective lens is:

1. 40 D
2. -4 D
3. -2.5 D
4. -0.25 diopter

✅ Correct Answer: 3

Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The effective power of the combination is:

1. 45 D
2. 9 D
3. 19 D
4. 6 D

✅ Correct Answer: 2

A blue cross on the white background is illuminated with white light and is observed through red filter. What is seen?

1. A red cross on a black background
2. A blue cross on a red background
3. A red cross on a blue background
4. A black cross on a red background

✅ Correct Answer: 4

The angle of deviation for a prism is greatest for:

1. violet
2. red
3. orange
4. yellow

✅ Correct Answer: 1

A double convex air bubble in water behaves as:

1. Convergent lens
2. divergent lens
3. plane slab
4. concave mirror

✅ Correct Answer: 2