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Solve the question in photo showing each step clearly
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Asked by Vidushi412 | 08 Apr, 2019, 08:23: AM
answered-by-expert Expert Answer
Power of light source = 2W
 
if metal surface is irradiated for 1s, photon Energy produced by the light source = 2W×1s = 2 Joules
 
In this 2 Joules photon energy, if each photon has energy 2×10-19 J, then number of photons = 2 /(2×10-19) = 1019 
 
If all the photons produced by lightsource is spherically distributed at a distance 1/√π m, 
then number of photons incident on metal surface of area 1 m2                                        =  1019 / (4π/π)
 
If each photon has knocked out a electron from metal surface, charge q left on metal surface is given by,
 
q = ( 1.602×10-19)×1019 / 4  C ≈  4 C
 
hence 10q  =   40C
Answered by Thiyagarajan K | 09 Apr, 2019, 08:25: AM

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