Chap#09 Physical Optics

Question 1

One cannot see through fog because:

Answer 1

Light is scattererd by the droplets in fog

Question 2

A sun rise or sun set, the sun looks reddish because:

Answer 2

Of the scattering of light

Question 3

A prism splits a beam of white light into ts seven constituent colors. This is so because:

Answer 3

Velcoity of different colors is different

Question 4

The twinkling of stars is due to:

Answer 4

The refractive index of the earth’s atmosphere fluctuate

Question 5

Light appears to travel in straight lines since:

Answer 5

Its wavelength is very small

Question 6

Which one of the following phenomena is not explained by Huygen’s construction of wavefront?

Answer 6

Origin of spectra

Question 7

If yellow light emitted by sodium lamp in Young’s double slit experiment is replaced by monochromatic blue light of the same intensity:

Answer 7

Fringe width will decrease

Question 8

In Young’s experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one metre away. If its produces the second dark fringe at a distance of 1mm from the central fringe, the wavelength of monochromatic light used would be:

Answer 8

6 x 10^-5 cm

Question 9

The contrast in the fringes in any interference pattern depends on:

Answer 9

Intensity ratio of the sources

Question 10

Huygen’s wave theory of light cannot explain:

Answer 10

Photo electric effect