A filter transmits only the radition of wavelength greater than 440 nm. Radition from a hydrogen discharge tube goes through such a filter and is incident on a metal of work function 2.0 e V. Find the stopping potential which can stop the photoelectrons.
λ = 440 nm,\\
Θ = Charge of the electron
Φ = 2 e V,
v0 = Stopping potential
We have hcλ−Φ=eV0
⇒4.14×10−15×3×108440×10−9−2eV=eV0eV0=(1242440−2)eV=0.823eV.
⇒v0=0.823Volts