JEE Main 2024 Physics question
An object is placed in a medium of refractive index 3. An electromagnetic wave of intensity 6 × 10⁸ W/m² 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 × 10⁸ m/s):
Answer: (A)
Solution
Speed of light in the medium c′ = c/3 = 10⁸ m/s. For complete absorption, P = I/c′ = 6 × 10⁸/10⁸ = 6 N m⁻².