Electromagnetic Waves Question 3
Question 3 - 2024 (27 Jan Shift 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 $=3 \times 10^{8} m / s$ ):
(1) $36 Nm^{-2}$
(2) $18 Nm^{-2}$
(3) $6 Nm^{-2}$
(4) $2 Nm^{-2}$
Show Answer
Answer: (3)
Solution:
Radiation pressure $=\frac{I}{v}$
$=\frac{I \cdot \mu}{c}$
$=\frac{6 \times 10^{8} \times 3}{3 \times 10^{8}}$
$=6 N / m^{2}$
