For completely reflecting surface, force, F=c2IA, where, I=SurfaceareaP is intensity of radiation, A is surface area and c is speed of light.
F=c2IπR2=24πR2P0cπR2
=2cP0=2×3×10824=4×10−8N
A point source of light is placed at the centre of curvature of a hemispherical surface. The source emits a power of 24W. The radius of curvature of hemisphere is 10cm and the inner surface is completely reflecting. The force on the hemisphere due to the light falling on it is ______ ×10−8N.
Held on 30 Jan 2023 · Verified 6 Jul 2026.
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