JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
Sun light falls normally on a surface of area \(36\,cm ^{2}\) and exerts an average force of \(7.2 \times 10^{-9}\,N\) within a time period of \(20\) minutes. Considering a case of complete absorption, the energy flux of incident light is.
- A \(25.92 \times 10^{2}\,W / cm ^{2}\)
- B \(8.64 \times 10^{-6}\,W / cm ^{2}\)
- C \(6.0\,W / cm ^{2}\)
- D \(0.06\,W / cm ^{2}\)
Answer & Solution
Correct Answer
(D) \(0.06\,W / cm ^{2}\)
Step-by-step Solution
Detailed explanation
\(\frac{I}{C} \times\) area \(=\) force \(\frac{I}{C} \times 36 \times 10^{-4}=7.2 \times 10^{-9}\) \(I =\frac{7.2 \times 10^{-9} \times 3 \times 10^{8}}{36 \times 10^{-9} \times 10}\) \(=\frac{6 \times 10^{-1}}{10^{-3}}\) \(I =6 \times 10^{2} \frac{ w }{ m ^{2}}\)…
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