JEE Main201911 Jan 2019Evening ShiftPhysicsDual Nature of MatterActual
In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm . The decrease in the stopping potential is close to : ( hc e =1240 nm - V )
Options
- A0.5 ~V
- B1.5 ~V
- C1.0 ~V
- D2.0 ~V
Correct answer
C. 1.0 ~V
Step-by-step solution
Let = work function of the metal, hc ₁ = + eV ₁ hc ₂ = + eV ₂ (ii) Sutracting (ii) from (i) we get hc ( 1 ₁ - 1 ₂ )= e ( V ₁- V ₂ ) V₁-V₂= h c e ( ₂- ₁ ₁ ₂ ) [ array l ₁=300 nm ₂=400 nm hc e =1240 nm - V array ]=(1240 nm - v ) ( 100 nm 300 nm 400 nm )=1,03 ~V 1 ~V