If in a photoelectric cell, the wavelength of incident light is changed from 4000 mathringA to 3000 mathringA then change in stopping potential will be

Question

If in a photoelectric cell, the wavelength of incident light is changed from 4000 mathringA to 3000 mathringA then change in stopping potential will be (A) 0.14 V (B) 0.24 V (C) 0.35 V (D) 1.04 V

Tardigrade Admin · Accepted Answer

The Einstein's equation for photoelectric effect is given

b ye V_{0} = \frac{h c}{λ} - W

where

V_{0} =

stopping potential,

h =

Planck's constant,

c =

velocity of light,

λ =

wavelength of incident light and

W =

work function of metal.
Here,

e V_{01} = \frac{h c}{λ _{1}} - W \dots (1)

and

e V_{02} = \frac{h c}{λ _{2}} - W \dots (2)

From

(1)

and

(2), e V_{02} = \frac{h c}{λ _{2}} + e V_{01} - \frac{h c}{λ _{1}}

e V_{02} - e V_{01} = \frac{h c}{λ _{2}} - \frac{h c}{λ _{1}}

V_{02} - V_{01} = (h c / e) [1/ λ_{2} - 1/ λ_{1}] = \frac{6.62 \times 1 0 ^{- 34} \times 3 \times 10}{1.6 \times 1 0 ^{- 19}} [\frac{1}{3000 \times 1 0 ^{- 10}} -

\frac{1}{4000 \times 1 0 ^{- 10}}] = 1.04 V

Q. If in a photoelectric cell, the wavelength of incident light is changed from 4000A˚ to 3000A˚ then change in stopping potential will be

0.14 V

0.24 V

0.35 V

1.04 V

Q. If in a photoelectric cell, the wavelength of incident light is changed from $4000 \overset{˚}{A}$ to $3000 \overset{˚}{A}$ then change in stopping potential will be