# Physics class -12th chapter 10 WAVE OPTICS MOST VVI Objective Question

Q.1. The colour of a thin film is due to

(A) scattering

(B) interference

(C) Dispersion

(D) diffraction

Ans :- (B)

Q.2. Brewster’s law is

(A) μ=sin ip

(B) μ=cos ip

(C) μ=tan ip

(D) μ=tan² ip

Ans :- (C)

Q.3. With increase in wavelength the refractive index

(A) Increases

(B) Decreases

(C) Remains unchanged

(D) None of these

Ans :- (B)

Q.4. Transverse nature of light is shown by

(A) Interference

(B) Reflection

(C) Polarisation

(D) Dispersion

Ans :- (C)

Q.5. The value of maximum amplitude produced due to interference of two waves is given by y₁ =4 sin wt and y₂ = 3 cos wt

(A) 7

(B) 5

(C) 1

(D) 25

Ans :- (B)

Q.6. The phase difference Φ is related to path difference Δx by

(A) λ/π Φ

(B) π/λ Φ

(C) λ/2π Φ

(D) 2π/λ Φ

Ans :- (C)

Q.7. Longitudinal waves do not exhibit

(A) reflection

(B) refraction

(C) diffraction

(D) polarisation

Ans :- (D)

Q.8. The transverse nature of light is shown by

(A) interference of light

(B) refraction of light

(C) polarisation light

(D) dispersion of light

Ans :- (C)

Q.9. Wave theory of light cannot explain

(A) reflection of light

(B) photo electric effect

(C) interference of light

(D) refraction of light

Ans :- (B)

Q.10. The colour of light is related to

(A) speed of light

(B) frequency

(C) amplitude

(D) None of these

Ans :- (B)

Q.11. When a red shirt is illuminated by green light, it appears

(A) black

(B) yellow

(C) green

(D) None of these

Ans :- (A)

Q.12. Young’s experiment establishes that consists of

(A) wave

(B) particles

(C) neither particles nor Waves

(D) none of these

Ans :- (A)

Q.13. If the angle of the biprism is increased the fringes width will

(A) increase

(B) decrease

(C) remain the same

(D) none of these

Ans :- (B)

Q.14. Colour in the films are due to

(A) total internal reflection

(B) interference

(C) dispersion

(D) all of the above

Ans :- (B)

Q.15. When viewed in white light soap bubbles show colour becouse of

(A) interference

(B) diffraction

(C) dispersion

(D) scattering

Ans :- (A)

Q.16. A diffraction grating

(A) has closely spaced and small number of rulings

(B) has closely spaced and large number of rulings

(C) dos not have ruling

(D) none of these

Ans :- (B)

Q.17. Which one of the following properties does not support Wave theory of light ?

(A) light obeys laws of reflection and refraction

(B) light waves get polarised

(C) light shows photoelectric effect

(D) light shows interference

Ans :- (C)

Q.18. Golden view of sea – shell is due to

(A) diffraction

(B) dispersion

(C) polarisation

(D) reflection

Ans :- (C)

Q.19. In case of linearly polarised light, the magnitude of the electric field vector

(A) is parallel to the direction of the propagation

(B) does not change with time

(C) increases and decreases linearly with time

(D) varies periodically with time

Ans :- (D)

Q.20. The angular fringe with does not depend upon

(A) wavelength (λ)

(B) distance between slits (d)

(C) distance between slits and screen (D)

(D) ration of λ/d

Ans :- (C)

Q.21. The width of diffraction band varies

(A) inversely as the wavelength

(B) directly as the width of the slit

(C) directly as the distance between the slit and the screen

(D) inversely as he size of the source from which the slit

Ans :- (C)

Q.22. The speed of light is a medium (say glass or water) does not depend upon

(A) nature of source

(B) direction of propagation

(C) both ‘A’and’B’

(D) wavelength

Ans :- (C)

Q.23. The speed of light in vacuum is universal constant. It is Independent of

(A) nature of source

(B) direction of propagation

(C) Wavelength

(D) All of above

Ans :- (D)

Q.24. Line spectrum is obtained by exciting

(A) atoms

(B) molecules

(C) solids

(D) none of these

Ans :- (A)

Q.25. The dark lines in solar spectrum are known as

(A) fraunofer lines

(B) Telluric lines

(C) both ‘A’and’B’

(D) none of these

Ans :- (A)

Q.26. What is the geometrical shape of a wave front of light diverging from a point source ?

(A) spherical

(B) Cylindrical

(C) Plane

(D) None of these

Ans :- (A)

Q.27. What is the shope of the wave front emitted by a light source in the form of a narrow slit ?

(A) Spherical

(B) Cylindrical

(C) Plane

(D) None of these

Ans :- (B)

Q.28. Two sources of monochromatic light are said to be coherent when their

(A) intersities are equal

(B) amplitudes are equal

(C) phase difference is constant

(D) none of these

Ans :- (C)

Q.29. The concept of secondary wavelets was introduced by

(A) Maxwell

(B) Newton

(C) Huygens

(D) none of these

Ans :- (C)

Q.30. Wave theory of light assumes that propagates from one place to other in the form of

(A) longitudinal waves

(B) transverse waves

(C) combination of transverse and longitudinal waves

(D) none of these

Ans :- (B)

Q.31. A monochromatic visible light consists of

(A) a single ray of light

(B) light of single wavelength

(C) light consisting of many wavelength ‘s with a single colour

(D) none of these

Ans :- (B)

Q.32. In Fresnel class of diffraction, the source is

(A) at finite distance from obstacle

(B) in clsoe contact with obstacle

(C) at infinite distance from obstacle

(D) none of these

Ans :- (A)

Q.33. According to wave motion-theory of light, the colour of light is decided by

(A) amplitude

(B) speed of wave

(C) frequency

(D) wavelength

Ans :- (C)

Q.34. The tangent of polarization angle is equal to the refractive index. This law is known as

(A) Malus law

(B) Brewster’s law

(C) Bragg’s law

(D) Compton’s law

Ans :- (B)

Q.35. Two sources of waves will be coherent when

(A) their amplitude is same

(B) their wavelength is same

(C) they produce waves of same velocity

(D) they produce waves of same wavelength and constant phase difference

Ans :- (D)

Q.36. In the biprism experiment we get interference fringes. The central fringe in this experiment is

(A) dark

(B) coloured

(C) bright

(D) none of these

Ans :- (C)