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A source of light is placed above a sphe...

A source of light is placed above a sphere of radius `10cm`. How many photoelectrons must be emitted by the sphere before emission of photoelectrons stop? The energy of incident photon is `4.2eV` and the work function of the metal is `1.5eV`.

A

`2.08 xx 10^(18)`

B

`1.875 xx 10^(8)`

C

`2.88 xx 10^(18)`

D

`4 xx 10^(19)`

Text Solution

Verified by Experts

The correct Answer is:
B
Stopping potential energy =`eV_(0)=E-omega`
`V_(0)=(E-omega)/e=(9xx10^(9)"ne")/r`,`n`=no of electrons
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