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Thermal Radiation. Quantum Nature of Light.

Problem 5.264

A plane light wave of intensity I=0.20 W/cm2I=0.20 \mathrm{~W} / \mathrm{cm}^{2} falls on a plane mirror surface with reflection coefficient ρ=0.8.\rho=0.8 . The angle of incidence is 45∘.45^{\circ} . In terms of the corpuscular theory find the magnitude of the normal pressure exerted by light on that surface

Reveal Answer
p=(I/c)(1+ρ)cos⁡2θ=0.6nN/cm2p=(I / c)(1+\rho) \cos ^{2} \theta=0.6 \mathrm{nN} / \mathrm{cm}^{2}
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