Question

calculate the stopping potential if a light of wavelength 500A°incidence on metal surface whose work function is 1•6e•v​

Answer 1

INCIDENT ENERGY IS GIVEN BY- 12400/WAVELENGTH

SO,incident will come out 2.48ev hence by the formula

Stopping potential =(2.48ev-1.60ev)/e=0.88v.

Answer 2

Given

Wavelength of the light λ =  500 Armstrong = 500 × 10⁻¹⁰

Work function φ₀ = 1.6 e V

Now from Einstein's photo electric equation eV = h(c/λ) - φ₀ -----(A)

Here h =planks constant  = 6.626 × 10⁻³⁴

c = speed of light = 3 × 10⁸ and

e = charge of an electron = 1.6 × 10⁻¹⁹

Now reducing the above mentioned value in A we get,

V = (hc/eλ) - φ₀/e

= (6.626 × 10⁻³⁴ ×3 × 10⁸)/(1.6 × 10⁻¹⁹ ×500 × 10⁻¹⁰ ) - (1.6 × 1.6 × 10⁻¹⁹)/(1.6 × 10⁻¹⁹)

= 24.8 - 1.6

Stopping potential 'V' = 23.2 volt