R P Goyal and S P Tripathi Solutions for Chapter: Spectrum, Exercise 1: EXERCISE-6(A)

Infrared radiations are used for photography in fog. Explain the reason.

Infrared radiations are used as signals during war. Explain the reason.

The photographic darkrooms are provided with infrared lamps. Explain the reason.

A rock salt prism is used instead of a glass prism to obtain the infrared spectrum.

Ultraviolet bulbs have a quartz envelope instead of glass. Explain the reason.

An electromagnetic wave has a frequency of $500 \mathrm{MHz}$ and a wavelength of $60 \mathrm{cm}$. Calculate velocity.

An electromagnetic wave has a frequency of $500 \mathrm{MHz}$ and a wavelength of $60 \mathrm{cm}$. Name the medium through which it is travelling.

The wavelength of X-ray is $1\stackrel{\circ }{\mathrm{A}}$. Calculate its frequency.