NCERT Class 12 Chapter 9 Physics Ray Optics and Optical Instruments MCQ

NCERT Class 12 Chapter 9 Physics Ray Optics and Optical Instruments MCQ | Questions & Answers: Want to learn about Chapter 9 Ray Optics and Optical Instruments in NCERT Class 12? well then here is the best article for you. Here we have arranged questions related to Ray Optics and Optical Instruments in a multiple-choice format which can help you in learning.

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1. The light reflected by a plane mirror may form a real image

A. if the rays incident on the mirror are diverging

B. if the rays incident on the mirror are converging

C. if the object is placed very close to the mirror

D. under no circumstances

2. For a total internal reflection, which of the following is correct?

A. Light travels from rarer to denser medium.

B. Light travels from denser to rarer medium.

C. Light travels in air only.

D. Light travels in water only.

3. Which of the following forms a virtual and erect image for all positions of the object?

A. Concave lens

B. Concave mirror

C. Convex mirror

D. Both (i) and (iii)

4. A convex and a concave mirror of radii 10 cm each are facing each other and 15 cm apart. A point object is placed midway between them. Then position of the final image if the reflection first takes place at the concave mirror and then in the convex mirror is

A. at the pole of the concave mirror

B. at the pole of the convex mirror

C. 5 cm behind the convex mirror

D. coincident with the object itself

5. In image formation from spherical mirrors, only paraxial rays are considered because they

A. are easy to handle geometrically

B. contain most of the intensity of the incident light

C. form nearly a point image of a point source

D. show minimum dispersion effect

6. Critical angle of glass is θ₂ and that of water is θ₂. The critical angle for water and glass surface would be (μ_g = 3/2, μ_w = 4/3).

A. less than θ₂

B. between θ₁ and θ₂

C. greater than θ₂

D. less than θ₁

7. Which of the following cannot be polarised?

A. radiowaves

B. transverse waves

C. sound waves

D. X-rays

8. When the object is located at the F of a concave mirror then

A. Image is of same size

B. image will be formed at infinity

C. Image is reduced in size

D. Image is magnified

9. For reflection through spherical surfaces, the normal at the point of incidence is

A. perpendicular to the principle axis and passes through the centre of curvature

B. perpendicular to the focal plane and passes through the pole.

C. perpendicular to the tangent plane at pole and passes through the focus

D. perpendicular to the tangent plane at the point of incidence and passes through the centre of curvature.

10. Mirage is a phenomenon due to

A. refraction of light

B. reflection of light

C. total internal reflection of light

D. diffraction of light.

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11. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Which one of the following is not possible?

A. The length of the telescope tube is 20.02 m.

B. The magnification is 1000

C. The image formed is inverted

D. An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image.

12. The focal length of a convex lens (refractive index = 1.5) in air is 20 cm. When immersed in water (refractive index = 1.33), its focal length will be

A. 20.2cm

B. 78.23 cm

C. 7.23 cm

D. 2.02 cm

13. A person is six feet tall. How tall must a plane mirror be if he is able to see his entire length?

A. 3 ft

B. 4.5 ft

C. 7.5 ft

D. 6 ft

14. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will

A. become zero

B. become infinite

C. become small, but non-zero

D. remain unchanged

15. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then

A. the magnification is 1000

B. the length of the telescope tube is 20.02 m

C. the image formed of inverted

D. all of these

16. In Concave Mirror

A. Reflecting surface is towards the centre of the sphere of which it can be considered as a cut off portion.

B. Reflecting surface is on the opposite side of the centre of the sphere of which it can be considered as a cut off portion.

C. Both a and b.

D. Concave mirror does not exist.

17. An object is placed 40 cm from a concave mirror of focal length 20 cm. The image formed is

A. real, inverted and same in size

B. real, inverted and smaller

C. virtual, erect and larger

D. virtual, erect and smaller

18. Which of the following forms a virtual and erect image for all positions of the object?

A. Concave lens

B. Concave mirror

C. Convex mirror

D. Both (a) and (c)

19. A concave mirror is held in water. What should be the change in the focal length of the mirror?

A. Halved

B. Doubled

C. Remains the same

D. Increases exponentially

20. In mirrors how can we differentiate real image from the virtual image

A. Real image is always inverted whereas virtual image is erect.

B. Real image is always twice in size as compared to virtual.

C. Real and virtual both are same.

D. Virtual image is always inverted whereas real is erect

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21. Which of the following is incorrect statement?

A. the magnification produced by a convex mirror is always less than one

B. a virtual, erect, same-sized image can be obtained using a plane mirror

C. a virtual, erect, magnifield image can be formed using a concave mirror

D. a real, inverted, same-sized image can be formed using a convex mirror.

22. Two lenses of focal lengths 20 cm and – 40 cm are held in contact. The image of an object at infinity will be formed by the combination at

A. 10 cm

B. 20 cm

C. 40 cm

D. infinity

23. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will

A. become zero

B. become infinite

C. become small, but non-zero

D. remain unchanged

24. ______ mirror is called as diverging mirror

A. Concave

B. Plane

C. Convex

D. Both b and c

25. Total internal reflection can take place only if

A. light goes from optically rarer medium (smaller refractive index) to optically denser medium

B. light goes from optically denser medium to rarer medium

C. the refractive indices of the two media are close to different

D. the refractive indices of the two media are widely different