Question

Human skin is relatively insensitive to visible light, but ultraviolet radiation can cause severe burns. Does this have anything to do with photon energies? Explain.

Short answer

The UV radiation has higher frequency than the threshold frequency of human skin thus the striking of UV light will definitely cause sever burns.

Step-by-step solution

(a) Concept of photoelectric effect.

The photoelectric effect is the ejection of surface electrons in a metal when photon strikes. The mathematical expression governing the effect and giving the maximum kinetic energy of the ejected electrons is,

$$\begin{gathered} \mathit{K}\mathbf{.}{\mathit{E}}_{\mathbf{m}\mathbf{a}\mathbf{x}}\mathbf{=}\mathit{h}\mathit{f}\mathbf{-}\mathit{\Phi } \\ \mathit{e}{\mathit{V}}_{\mathbf{0}}\mathbf{=}\mathit{h}\mathit{f}\mathbf{-}\mathit{h}{\mathit{f}}_{\mathbf{0}} \end{gathered}$$

Where $\Phi$the work function, hf is the energy of the striking photon, f₀ is the threshold frequency and V₀ is the stopping potential.

(b) Explanation of the argument.

The photons have high energy in ultraviolet radiations and high energy means higher frequency than the threshold frequency. So, the striking light has frequencies greater-than the work function of the human skin which will eventually ionize the skin cells. Therefore, the human skin will show chemical effects and will burn.