Chapter 18, Problem 28P

Interpretation Introduction

Interpretation: The method how sunscreens prevent UV radiation from reaching the skin should be explained.

Concept Introduction: The strongest source of ultraviolet (UV) radiation in our environment is sun. These radiations penetrate the Earth’s ozone layer and are classified into two regions on the basis of their wavelengths:

• UVA ( $\text{320-400 nm}$)
• UVB ( $\text{290-320 nm}$ )