A Level Physics Practice Exam - 2026 Practice Test & Study Guide

The frequency of a light wave can be calculated using the relationship between the speed of light, its frequency, and its wavelength. The fundamental formula that relates these quantities is expressed as the speed of the wave (v) equals the frequency (f) multiplied by the wavelength (λ), represented as v = f × λ.

From this equation, you can derive two other forms as well. By rearranging the original equation to solve for frequency, you arrive at f = v / λ. Similarly, if you solve for wavelength, you get λ = v / f.

All three forms are essentially manifestations of the same relationship and can be used interchangeably depending on which variable you are solving for. Therefore, stating that all of the equations are valid forms of expressing the relationship between speed, wavelength, and frequency is accurate. This comprehensive view highlights the important interconnectedness of these physical concepts in the study of waves, especially in optics.