Light with an energy flux of $25 \times {10^4}$ $W/m^2$ 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
Light with an energy flux of $25 \times {10^4}$ $W/m^2$ 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
- [AIPMT 2014]
- A
$1.25\times 10^{-6}\;N$
- B
$2.50\times 10^{-6}\;N$
- C
$1.2\times 10^{-6}\;N$
- D
$3 \times 10^{-6}\;N$
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