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An electromagnetic wave with pointing ve...

An electromagnetic wave with pointing vector 5 `W//m^(2)`is absorbed by a surface of same area. If the force on the surface is `10^(-7)`N, then area is

A

`6m^(2)`

B

`3m^(2)`

C

`60m^(2)`

D

`4m^(2)`

Text Solution

Verified by Experts

(a) We know `,P=(I)/(c)=(5)/(3xx10^(8))`
and `F=PxxA implies A=(F)/(P)`
`A=(10^(-7))/(5)xx3 xx10^(8)implies A=6 m^(2)`
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