Question

What is the force exerted by a photon of intensity 1.4 kWm^–2 if it falls on a perfect absorber of radius 2 meter?

• A. 2.35 × 10^–4 N
• B. 10⁸ N
• C. 8.35 × 10⁴ N
• D. 8.8 × 10^–8 N

Answer 1

Answer: (A)

2.35 × 10^–4 N

Answer 2

P = = $\frac { 1.4 \times 10 ^ { 3 } } { 3 \times 10 ^ { 8 } }$

Force = P × A