• question_answer Give reason of the following (i) The momentum that is transferred by an electromagnetic wave on a surface is very small. (ii) Childrens are always warned to not to look directly from their naked eyes when a welder is welding a part of a machine.

(i) As we know, Momentum transferred     $\text{=}\frac{\text{Energy}}{\text{Speed}\,\text{of}\,\text{light}}$                                     $=\frac{E}{c}=\frac{hv}{c}={{10}^{-22}}$ Thus, the amount of the momentum transferred by the electromagnetic waves incident on the surface is very small. (ii) During welding, ultraviolet rays are released, which can harm the eyes, if seen through naked eyes. Hence, childrens are warned to not to see it directly