A point source of power 450 W is emitting light in all direction. Radiation pressure at distance of 2m from the source is nearly (1) 3 × 10^–8 Pa

Question

A point source of power 450 W is emitting light in all direction. Radiation pressure at distance of 2m from the source is nearly

(1) \(3 \times 10^{-8} \ Pa\)

(2) \(2 \times 10^{-8} \ Pa\)

(3) \(2 \times 10^{-9} \ Pa\) 

(4) \(4 \times 10^{-7} \ Pa\)

Answer 1

Correct option is:  (1) \(3 \times 10^{-8} \ Pa\)

\(p = \frac{I}{C} = \frac{P}{AC} = \frac{450}{4 \times 3.14 \times 2^2 \times 3 \times 10^8} = \frac{450}{48 \times 3.14} \times 10^{-8}\)

\(\approx 3 \times 10^{-8} \ Pa\)