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Encircle the correct option. 1. In Young’s double slit experiment, the position of bright fringe from the center of screen is given by a) 𝑦 =

𝑚ƛL 𝑑

b) 𝑦 =

𝑚ƛL 2𝑑

c) 𝑦 =

2𝑚ƛL 𝑑

d) 𝑦 =

𝑚ƛ 𝑑

2. Blue color of sky is due to a) Dispersion b) Scattering c) Interference d) Polarization 3. In diffraction grating the path difference for constructive interference should be a)

ƛ 2

b)

ƛ 4

c)

ƛ 8

d) ƛ

4. In interference of thin films, the path difference depends upon a) Angle of incidence b) Angle of refraction c) angle of deviation 5. A typical diffraction grating has about a) 400 to 5000 lines/m b) 400 to 5000 lines/cm c) 400 to 5000 lines/m3 6. Michelson’s interferometer can also be used to find the a) The frequency of light b) the wavelength of light c) velocity of light 7. In diffraction pattern due to narrow slits the equation for the first minimum is a)

𝑑 𝑠𝑖𝑛𝜃 2

= ƛ

b)

𝑑 𝑠𝑖𝑛𝜃 2

=

ƛ 2

c) 𝑑 𝑠𝑖𝑛𝜃 =

ƛ 𝑑 𝑠𝑖𝑛𝜃 d) 2 2

=

d) none d) 400 to 5000 lines/mm d) velocity of sound

2ƛ 3

8. According to Huygen’s principle, every point of a wavefront may be considered as a source of a) Primary wavelet b) Secondary wavelets c) source wavelets d) none 9. The tip of a needle does not give a sharp image. It is due to a) Polarization b) Interference c) Refraction d) Diffraction 10. The principle of Michelson’s interferometer is based on the division of a) Wavefront b) Amplitude c) Frequency d) Speed of light 11. Light of wavelength ƛ is incident normally on a diffraction grating for which the slit spacing is equal to 3 ƛ . What is the sine Of angle between the second order maxima and the normal is a)

1 6

b)

1 3

c)

2 3

d) 1

12. Diffraction of light prove the a) Wave nature of light b) particle nature of light c) wave-particle nature of light d) none 13. A monochromaic light consist of a) One color b) two colors c) seven colors d) none 14. In Young’s experiment, the spacing of fringes can be controlled by changing a) Distance between slits b) Distance between slits and screen c) color of light d) all 15. The Polarizing angle for a glass of refractive index 1.55 is, (assuming the light is coming from air to glass) a) 570 b) 600 c) 900 d) 230 16. In X-rays diffraction from crystal, if the spacing between the two consecutive planes/layers is doubled, then Bragg’s law is a) 𝑑 𝑠𝑖𝑛𝜃 = mƛ b) 2𝑑 𝑠𝑖𝑛𝜃 = mƛ c) 4𝑑 𝑠𝑖𝑛𝜃 = mƛ d) 3𝑑 𝑠𝑖𝑛𝜃 = mƛ 17. Coloured fringes observed in soap bubbles are the example of a) Diffraction b) Interference c) Polarization d) Reflection 18.