Arrange the following types of electromagnetic waves in the increasing order of their frequencies.
A. Gamma rays
B. Radio waves
C. Visible light
D. Ultraviolet rays
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B < C < D < A
For electromagnetic waves \( \nu = c/\lambda \), so the shorter the wavelength, the higher the frequency. Typical wavelengths in the electromagnetic spectrum:
\( \text{B. Radio waves: } \lambda \gt 0.1\,\mathrm{m} \)
\( \text{C. Visible light: } 700\,\mathrm{nm} \text{ to } 400\,\mathrm{nm} \)
\( \text{D. Ultraviolet rays: } 400\,\mathrm{nm} \text{ to } 1\,\mathrm{nm} \)
\( \text{A. Gamma rays: } \lambda \lt 10^{-3}\,\mathrm{nm} \)
The wavelength decreases from B to C to D to A, so the frequency increases in the same order:
\( B \lt C \lt D \lt A \)
NCERT (2026-27):
Summary – “… 6. The spectrum of electromagnetic waves stretches, in principle, over an infinite range of wavelengths. Different regions are known by different names; γ-rays, X-rays, ultraviolet rays, visible rays, infrared rays, microwaves and radio waves in order of increasing wavelength from 10–2 Å or 10–12 m to 106 m.”