Q79 / 90 · JEE Main 2019 (09 Apr Shift 2) · Physics

Sunlight of intensity 50 W m-2 is incident normally on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1 m2 surface area will be close to c=3×108 m s-1

  • A
    15×10-8 N
  • Correct answer
    B
    20×10-8 N
  • C
    10×10-8 N
  • D
    35×10-8 N

Solution

The pressure exerted by the photons

 P=0.75×Ic +0.25×2Ic ( P = pressure, c = speed of light, I = intensity )

P=1.25 ×Ic

 We know the force can be computed using

F=P×A 

( F = force, P = pressure, A = area )

F=1.25×50×13×108

F=20.83×10-8 N

Hence, the correct answer is option: 'B'.

Relevant Questions