Dual Nature of Matter

JEE Main level, single correct, medium

103 of 200

Question 103 of 200

The radiation pressure exerted by a 450 W light source on a perfectly reflecting surface placed at 2 m away from it, is :

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Answer: (C) 6×10−86 \times 10^{-8} Pascals

Prad=2ICP_{\mathrm{rad}}=\frac{2 I}{\mathrm{C}}
Where I=\mathrm{I}= intensity at surface
C=\mathrm{C}= Speed of light
$\begin{aligned}
& I=\frac{\text { Power }}{\text { Area }}=\frac{450}{4 \pi \mathrm{r}^2} \\
& =\frac{450}{4 \pi \times 4}=\frac{450}{16 \pi} \\
& P_{\mathrm{rad}}=\frac{2 \times 450}{16 \pi \times 3 \times 10^8}=\frac{150}{8 \pi \times 10^8}
\end{aligned}$
=5.97×10−8≈6×10−8=5.97 \times 10^{-8} \approx 6 \times 10^{-8} Pascals

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