NCERT Class 12 Chapter 10 Physics Wave Optics MCQ

NCERT Class 12 Chapter 10 Physics Wave Optics MCQ | Questions & Answers: Do make use of the MCQ Quiz that we have included here to enhance your knowledge about the NCERT Class 12 Chapter 10 Physics Wave Optics topic. After submission of your quiz don’t forget to check your marks to know where you stood with regards your knowledge about wave optics concept.

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1. Wavefront is the locus of all points, where the particles of the medium vibrate with the same

A. phase

B. amplitude

C. frequency

D. period

2. The idea of secondary wavelets for the. propagation of a wave was first given by

A. Newton

B. Huygens

C. Maxwell

D. Fresnel

3. The phenomena which is not explained by Huygen’s construction of wavefront

A. reflection

B. diffraction

C. refraction

D. origin of spectra

4. For sustained interference we need two sources which emit waves:

A. with same amplitude

B. with same intensity

C. in a narrow beam

D. having constant phase difference

5. A plane wave passes through a convex lens. The geometrical shape of the wavefront that emerges is

A. plane

B. diverging spherical

C. converging spherical

D. None of these

6. Light propagates rectilinearly, due to

A. wave nature

B. wavelengths

C. velocity

D. frequency

7. When a polaroid is rotated, the intensity of light varies but never reduces to zero. It shows that the incident light is:

A. unpolarised

B. completely plane polarised

C. partially plane polarised

D. None of the above

8. When the interference occurs with coherent sources, _______ of the superimposing
waves add like _______.

A. intensities, scalars

B. amplitudes, vectors

C. amplitudes, scalars

D. intensities, vectors

9. Huygen’s concept of secondary wave

A. allows us to find the focal length of a thick lens

B. is a geometrical method to find a wavefront

C. is used to determine the velocity of light

D. is used to explain polarisation

10. Which of the following is correct for light diverging from a point source?

A. The intensity decreases in proportion with the distance squared.

B. The wavefront is parabolic.

C. The intensity at the wavelength does not depend on the distance

D. None of these.

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11. In a Young’s doubles-slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case

A. there shall be alternate interference patterns of red and blue.

B. there shall be an interference pattern for red distinct from that for blue.

C. there shall be no interference fringes.

D. there shall be an interference pattern for red mixing with one for blue

12. Two sources of light are said to be coherent when both give out light waves of same:

A. phase and speed

B. wave length and constant phase difference

C. intensity and wavelength

D. amplitude and phase

13. The interfering fringes formed by a thin oil film on water are seen in yellow light of sodium lamp. We find the fringes

A. coloured

B. black and white

C. yellow and black

D. coloured without yellow

14. The refractive index of glass is 1.5 for light waves of X = 6000 A in vacuum. Its wavelength in glass is

A. 2000 Å

B. 4000 Å

C. 1000 Å

D. 3000 Å

15. Wavefront is the locus of all points, where the particles of the medium vibrate with the same

A. phase

B. amplitude

C. frequency

D. period

16. Phase difference between two coherent sources should be:

A. zero

B. πn rad

C. π rad

D. π/2 rad

17. Two coherent sources of intensity ratio 1 : 4 produce an interference pattern. The fringe visibility will be

A. 1

B. 0.8

C. 0.4

D. 0.6

18. The phenomenon which is not explained by Huygen’s construction of wavefront

A. reflection

B. diffraction

C. refraction

D. origin of spectra

19. Identify the condition which is not necessary for two light waves to be coherent.

A. The two waves must be continuous

B. The two waves should be of the same frequency or wavelength

C. They should have a constant or zero phases difference

D. They two light sources should be narrow

20. Coherent sources can be created by the division of:

A. only amplitude

B. only wave front

C. only wavelength

D. both amplitude and wave front

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21. The fringe width in a Young’s double slit experiment can be increased if we decrease

A. width of slits

B. separation of slits

C. wavelength of light used

D. distance between slits and screen

22. A laser beam is used for locating distant objects because

A. it is monochromatic

B. it is not chromatic

C. it is not observed

D. it has small angular spread.

23. The interfering fringes formed by a thin oil film on water are seen in yellow light of sodium lamp. We find the fringes

A. coloured

B. black and white

C. yellow and black

D. coloured without yellow

24. In a Fresnel's biprism experiment, the two coherent sources are obtained by:

A. two slits

B. reflection

C. Refraction

D. Internal reflection

25. If Young’s double slit experiment is performed in water keeping the rest of the set-up same, the fringes will

A. increase in width

B. decrease in width

C. remain unchanged

D. not be formed