photoelectric affect experiments are performer using ther different medal plates `p,q` and`r` having work function``phi_(p) = 2.0 eV, phi_(e) = 2.5 eV` and`phi_(r) = 3.0 eV` respectively A light beam containing wavelength of `550nm , 450 nm` and `350nm ` with equal intensities illuminates each of the plate . The correct `1 -V` graph for the experiment is` [Take hc = 1240 eV nm]`

Options

A.
B.
C.
D.

Answer

A

Explanation

The energy possessed by photons of wavelength
`550 nm is (1240)/(550) = 2.25 eV`
The energy by photons of wavelength
`450 is (1240)/(450) = 2.76 eV`
The energy possessed by photons of wavelength
`3450 nm is (1240)/(350) = 3.54 eV`
For metal plate p :
`phi_(p) = 2 eV`
All the wavelength are capable of ejecting electrons . Therfore the currect is maximum . Also as the work function is loewst in p, kinetic energy of ejected potential is bighast.
for mjatal plate q :
`phi_(q) = 25 eV`
photoes of wavelength `550` nm will not be able to iject electrons and therefore , the currect is smaller than p . The work function is greater then q therfore the stopping potential in compararison to p.
for metal plate r :
`phi _(r) = 3 eV` Only wavelength of `350` nm will be able to eject and therefore , currect is minimum. Also the stopping potential is least.