Question

Explain the relationship between wavelength and frequency of a wave. Illustrate your answer with the help of a diagram.

Answer 1

The relationship between wavelength and frequency of a wave is a fundamental concept in wave physics. Wavelength (λ) is the distance between two consecutive crests or troughs of a wave, while frequency (f) refers to the number of complete wave cycles passing a point per second. The speed of a wave (v) is given by the product of its wavelength and frequency, expressed as v = f × λ. This relationship means that if the speed of the wave remains constant (as with electromagnetic waves in a vacuum, which travel at the speed of light), the wavelength and frequency are inversely related: when one increases, the other decreases. In simpler terms, long waves have a low frequency, while short waves have a high frequency.

This relationship is visually illustrated in the diagram below. In Fig. the top wave shows a long wavelength and low frequency, with few wave cycles. As you move down the diagram, the wavelength becomes shorter, and the number of wave cycles (frequency) increases. The bottom wave in the diagram clearly demonstrates a very short wavelength and very high frequency. This inverse relationship between wavelength and frequency is a fundamental principle of wave behaviour, seen across the electromagnetic spectrum from long radio waves to short gamma rays.