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(C) When a light beam is incident at an angle of incidence $	heta$,the effective intensity on the surface is $I \cos 	heta$ and the effective area i

Vedclass · Accepted Answer

$\frac{2IA \cos^2 	heta}{c}$

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(C) When a light beam is incident at an angle of incidence $	heta$,the effective intensity on the surface is $I \cos 	heta$ and the effective area is $A \cos 	heta$. The momentum transferred per unit time per unit area by the incident light is $\frac{I \cos 	heta}{c}$. The normal component of this momentum transfer is $\frac{I \cos 	heta}{c} 	imes \cos 	heta = \frac{I \cos^2 	heta}{c}$.Since the surface is perfectly reflecting,the reflected light also exerts an equal pressure due to the change in momentum. The total radiation pressure $p_{	ext{net}}$ is the sum of the pressure due to incident and reflected light:$p_{	ext{net}} = \frac{I \cos^2 	heta}{c} + \frac{I \cos^2 	heta}{c} = \frac{2I \cos^2 	heta}{c}$.The force $F$ exerted on the surface of area $A$ is given by $F = p_{	ext{net}} 	imes A$.Therefore,$F = \frac{2IA \cos^2 	heta}{c}$.

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