JEE PYQ: Electromagnetic Induction Question 2
Question 2 - 2021 (17 Mar Shift 1)
If $2.5 \times 10^{-6}$ N average force is exerted by a light wave on a non-reflecting surface of $30$ cm$^2$ area during 40 minutes of time span, the energy flux of light just before it falls on the surface is ______ W/cm$^2$.
(Round off to the Nearest Integer)
(Assume complete absorption and normal incidence conditions are there)
Show Answer
Answer: 25
Solution
$F = \frac{IA}{c}$. Therefore $I = \frac{Fc}{A} = \frac{2.5 \times 10^{-6} \times 3 \times 10^{8}}{30} = 25$ W/cm$^2$.
BETA
