A horizontal cesium plate ( ϕ = 1.9 eV) is moved vertically downward at a constant speed v in a room full of radiation of wavelength 250 nm and above. What should be the minimum value of v so that the vertically upward component of the velocity is non-positive for each photoelectron?

Question

Philoid · Accepted Answer

Given, wavelength λ=250nm

Work function Ф =1.9eV

We know that energy of photon =

From Einstein’s photoelectric equation

For minimum value of v so that the vertically upward

Component of the velocity is non-positive for each

Photoelectron. We know that,

Velocity of photoelectron

A horizontal cesium plate (ϕ = 1.9 eV) is moved vertically downward at a constant speed v in a room full of radiation of wavelength 250 nm and above. What should be the minimum value of v so that the vertically upward component of the velocity is non-positive for each photoelectron?