WAEC Physics 2018 Paper

Concept:The energy of an electromagnetic wave depends on its frequency or wavelength.Explanation:Energy of a photon is given by $E = hf = \frac{hc}{\lambda}$.Here, $h$ is Planck's constant, $c$ is the speed of light, $f$ is frequency, and $\lambda$ is wavelength.So, shorter wavelength means higher frequency and higher energy.Among the given options, gamma rays have the shortest wavelength and the highest frequency.Therefore, gamma rays carry the most energy per photon.Answer:C. Gamma rays