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JEE Main202117 Mar 2021Morning ShiftPhysicsElectromagnetic WavesActual

If 2 . 5 × 10 - 6 N average force is exerted by a light wave on a non-reflecting surface of 30 cm 2 area during 40 min 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)

Correct answer

0

Step-by-step solution

F = I A c ⇒ I = F c A = 2 . 5 × 10 - 6 × 3 × 10 8 30 = 25   W   cm - 2

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