Photoelectric effect experiments are performed using three different metal 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 plates . The correct `I -V` graph for the experiment is [Take hc = 1240 eV nm]

Options

A.
B.
C.
D.

Answer

A

Explanation

`E_(lambda1) =550 nm =(1242)/(550)eV =2.25 eV`
`E_(lambda2) =450 nm =(1240)/(450)eV =2.8 eV`
`E_(lambda3) =350 nm =(1242)/(350)eV =3.5 eV`
From plate p, electrons are ejected by wave lengths 550, 450 and 350 nm
From plate q electrons are ejected by wavelength 450 and 350 nm
From plate r electrons are ejected by wave length 350 nm