The collecter of the photocell (in photoelectric experiment ) is made of tugsten while the emitter is Platinum having work function of `10 eV`.Monochromotic radiation of wavelength `124 Å` & power `100 ` watt is incident on emitter which emits photo electrons with a quantum efficiency of `1%`.The accelerating voltage acros the photocell is of `10,000` volts (Use: `hc=12400eV Å`)
What is the power supplied by the accelerating voltage source.

Options

A. `100` watt
B. `10` watt
C. `0.1` watt
D. `1` watt

Answer

A

Explanation

`P=V i_(S)`
where `V`=accelerating voltange
`i_(S)`=saturated photocurrent
`i_(S)=("Power of source of light"xx "Quantum efficiency" xx lambda("in"Å))/12400`
`=(100xx0.1xx124)/12400=0.01A, therefore "Power"=100W`