Get Answers to all your Questions

header-bg qa

A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is

A. blue
B. green
C. violet
D. red

Answers (1)

The emerging colour would be (d) red, because of the relation v=f\lambda , which provides the velocity of a wave. During the changing of the mediums, the frequency of the wave remains constant. So, v\; \alpha \lambda or wavelength is directly proportional to speed.

As red colour has the highest wavelength in the spectra, it also has the highest speed according to tot eh relation. Hence, when the light travels in the slab, the first colour to emerge is red.

Posted by

infoexpert23

View full answer