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Two monochromatic beam A and B of equal ...

Two monochromatic beam A and B of equal intensity I,hit a screen.The number of photons hitting the screen by beam A is twice that by beam B.Then what inference can you make about their frequencies?

Text Solution

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Intensity of light is given by,
`I=(E_(n))/(At)=(nhf)/(At)`
(Where A=area of given screen)
`therefore I=m.hf`
where n.=`(n)/(At)`=no. of photon incident of unit unit area of screen per unit time
`therefore n.f=(I)/(h)`=constant(`because` Here I is constant)
`therefore n._(A)f_(A)=n._(B)f_(B)` (As per the statement)
`therefore f_(A)=(f_(B))/(2)`
`implies` Frequency of beam A would be half of frequency of beam B.
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