Radiation pressure

2014 AIPMT 1 question

1. 1 Electromagnetic Waves Medium
   Light with an energy flux of $25\times10^4$ $Wm^{-2}$ falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 $cm^2$, the average force exerted on the surface is:
   A $1.25\times10^{-6}$ N B $2.50\times10^{-6}$ N C $1.20\times10^{-6}$ N D $3.0\times10^{-6}$ N
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