Light with an average flux of $20 \mathrm{W} {\mathrm{cm}}^{-2}$ falls on a non-reflecting surface at normal incidence having surface area $20 {\mathrm{cm}}^2$. The energy received by the surface during time span of $1 \min$ is:

• A

  $12\times {10}^3 \mathrm{J}$
• Correct answer
  B

  $24\times {10}^3 \mathrm{J}$
• C

  $48\times {10}^3 \mathrm{J}$
• D

  $10\times {10}^3 \mathrm{J}$

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