Question

Arrange the following radiations in the order of their increasing wavelength:
$X$-rays, infra red rays, radio waves, gamma rays and micro waves.

• A. Gamma rays, $X$-rays, infra red rays, radio waves, micro waves.
• B. Gamma rays, micro waves, $X$-rays, infra red rays, radio waves.
• C. Gamma rays, infra red rays, $X$-rays, micro waves, radio waves.
• D. Gamma rays, $X$-rays, infra red rays, micro waves, radio waves.

Answer 1

The correct option is D Gamma rays, $X$-rays, infra red rays, micro waves, radio waves.

Electromagnetic radiation is classified into types according to the frequency of the wave. These types include, in order of increasing frequency, radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
The frequency is the inverse of wavelength. Hence, in the order of increasing wavelength, the waves are Gamma rays ($<1nm$), X-rays (1-10 nm), infra red rays ($700-{10}^{5}nm$), micro waves (${10}^5-{10}^{8}nm$), radio waves (${>10}^{8}nm$).