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We know that the Sun is fundamental source of all energy that we use. Huge amount of energy is being produced in the Sun and this energy is radiated all around in the form of electromagnetic waves of several possible wavelengths. We can treat the Sun as a point source because it radiates energy uniformly in all directions. Intensity of wave at a point is defined as amount of energy passing that point per unit time and per unit area. We know that Earth is at a distance approximately 1.5 xx10^(11) m from the Sun and assume that intensity of radiation of the Sun reaching Earth's surface is 10^3 W/m^2. Howmuchforceis applied by the radiationon aroofis size9 m xx 10 m.Assumethat matericalof roofis perfectlyabsorbing . |
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Answer» `2XX 10^(-4)N` ` F= (U )/( c) = (IA )/(c ) = ( 10 ^3 xx 90 ) /( 3xx 10^8 ) = 3xx 10^(-4) N` |
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