Question

The number of photons emitted by a 10 watt bulb in 10 seconds, if the wavelength of light is 1000 Aº
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Answer 1

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Answer 2

Given:

Power of bulb               = 10 $watt$

Time                               =  10 $sec$

Wavelength (λ) of  light    =  1000 $A$°

To Find:

No. of the Photons = ?

Solution:

Power of bulb is 10 $watt$

Power is energy with per unit of time in seconds is in watt

So Energy in 1 seconds   = 10 $J$

     Energy in 10 seconds = 100  $J$

   

Energy is required for removing out one proton =  h × c / λ

       =    $6.63$ ×$10^{-34}$ × $3$ × $10^{8}$ / 1000 × $10^{-10}$

       = $19.89$ × $10^{-16}$

No. of the photons = 100 / 19.89 × $10^{-16}$

                                 = 5.027 × $10^{16}$