Question

In the photoelectric effect, the maximum kinetic energy of the emitted photoelectron is ‘a’ and the work function of the metal is W₀. If the frequency of incident radiation is made ‘K’ times, then calculate the change in maximum KE of the ejected electron.

Answer 1

Given a = hv – W₀

⇒ hv = a + W₀

New frequency = Kν

`K_"max"^'` = h(Kν) – W₀

= Khv – W₀

Change in maximum kinetic energy:

`ΔK_"max" = K_"max"^' - a`

= (khv – W₀) – (hv – W₀)

= (K – 1)hv 

Now substitute hν = a + W₀​:

ΔK_max = (K – 1) (a + W₀​)