Light with an energy flux of $25\times {10}^4 {\mathrm{W} \mathrm{m}}^{-2}$ falls on a perfectly reflecting surface at normal incidence. If the surface area is $15 {\mathrm{c}\mathrm{m}}^2,$ the average force exerted on the surface is:

• A

  $1.25\times {10}^{-6}\mathrm{N}$
• Correct answer
  B

  $2.50\times {10}^{-6}\mathrm{N}$
• C

  $1.20\times {10}^{-6}\mathrm{N}$
• D

  $3.0\times {10}^{-6}\mathrm{N}$

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