Physics Circle home Student Login

Home›Chapters›Electromagnetic Waves PYQs›Momentum & Radiation Pressure›Question 7

JEE Main 2022 (28 Jul, Shift 2) · Momentum & Radiation Pressure

Momentum & Radiation Pressure question from JEE Main 2022 (28 Jul, Shift 2)

Q7JEE Main 2022 · 28 JUL · SHIFT 2Medium

Momentum & Radiation Pressure

Sun light falls normally on a surface of area 36 cm236\text{ cm}^{2} and exerts an average force of 7.2×10−9 N7.2 \times 10^{-9}\text{ N} within a time period of 20 minutes. Considering a case of complete absorption, the energy flux of incident light is

Show answer and solution

Answer: (d)

  1. Complete absorption: F=IAc⇒I=FcAF = \dfrac{IA}{c} \Rightarrow I = \dfrac{Fc}{A}
  2. I=7.2×10−9×3×10836 cm2=2.16 W36 cm2I = \dfrac{7.2 \times 10^{-9} \times 3 \times 10^8}{36\ \text{cm}^2} = \dfrac{2.16\ \text{W}}{36\ \text{cm}^2}
  3. I=0.06 W/cm2I = 0.06\ \text{W/cm}^2, so the answer is (d).
Report a mistake

More questions on Momentum & Radiation Pressure