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(C) The radiation pressure $P$ exerted by an electromagnetic wave on a surface that absorbs it completely is given by the formula $P = \frac{I}{v}$,wh

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$6$

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(C) The radiation pressure $P$ exerted by an electromagnetic wave on a surface that absorbs it completely is given by the formula $P = \frac{I}{v}$,where $I$ is the intensity of the wave and $v$ is the speed of the wave in the medium.The speed of the wave in a medium with refractive index $n$ is given by $v = \frac{c}{n}$,where $c$ is the speed of light in free space.Substituting $v$ into the pressure formula,we get $P = \frac{I \cdot n}{c}$.Given:Intensity $I = 6 	imes 10^8 \ W/m^2$Refractive index $n = 3$Speed of light $c = 3 	imes 10^8 \ m/s$Calculating the pressure:$P = \frac{(6 	imes 10^8) 	imes 3}{3 	imes 10^8}$$P = 6 \ N/m^2$.

An object is placed in a medium of refractive index $3$. An electromagnetic wave of intensity $6 \times 10^8 \ W/m^2$ falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space $= 3 \times 10^8 \ m/s$): (in $N/m^2$)

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