A plane light wave of intensity I = 0.20 W//cm^(2) falls on a plane mirror surface with reflection coefficient rho = 0.8. The angle of incidence is 45^(@). In terms of the corpuscular theory find the magnitude of the normal pressure extered by light on that surface.

A plane light wave of intensity I = 0.20 W//cm^(2) falls on a plane mi

1.	A plane light wave of intensity I = 0.20 W//cm^(2) falls on a plane mirror surface with reflection coefficient rho = 0.8. The angle of incidence is 45^(@). In terms of the corpuscular theory find the magnitude of the normal pressure extered by light on that surface.
Answer» Solution :Suppose the mirror has a surtace AREA `A`. The incident BEAM then has a cross section of `A cos theta` and the incident enegry is `IA cos theta`: Then the momentum transferred per second `(=` FORCE) is from the lest PROBLEM `-(IA cos theta)/(c ) (1+rho)cos theta hatj +(IA cos theta)/(c ) (1-rho)sin theta hati` The normal pressure is then `p = (I)/(c)(1+rho)cos^(2)theta (hatj` is the unit vector `_\|_^(r )` to the plane mirror). Putting in the values `p = (0.20xx10^(4))/(3XX10^(8)) xx1.8 xx (1)/(2) = 0.6nNcm^(-2)`

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A plane light wave of intensity I = 0.20 W//cm^(2) falls on a plane mirror surface with reflection coefficient rho = 0.8. The angle of incidence is 45^(@). In terms of the corpuscular theory find the magnitude of the normal pressure extered by light on that surface.

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