An object is placed in a medium of refractive index 3 . An electromagnetic wave of intensity 6 × 10 8 W m - 2 falls normally on the object and it is absorbed completely. The radiation pressure on the

Question

An object is placed in a medium of refractive index 3 . An electromagnetic wave of intensity 6 × 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 × 10 8 m s - 1 ):

TestHub · Accepted Answer

The formula to calculate the radiation pressure is given by

$P = \frac{I}{v} . . . (1)$

Also, the velocity of the electromagnetic wave can be expressed as

$μ = \frac{c}{v} . . . (2)$

Equations (1) and (2) imply that

$\begin{array}{rcl} P & = & \frac{I \cdot μ}{c} \\ = & \frac{6 \times 10^{8} \times 3}{3 \times 10^{8}} \\ = & 6 N m^{- 2} \end{array}$

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