Question

When photons of energy hv fall on a metal plate of work function 'W₀', photoelectrons of maximum kinetic energy 'K' are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be ______.

विकल्प

• K + W₀

• K + hv

• K

• 2K

Answer 1

When photons of energy hv fall on a metal plate of work function 'W₀', photoelectrons of maximum kinetic energy 'K' are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be K + hv.

Explanation:

Given, energy of photon = hv,

work function = W₀

and maximum kinetic energy = K

So, from the Einstein's photoelectric equation,

E = K + W₀ ⇒ hv = K + W₀

⇒ K = hv - W₀   ...(i)

If frequency of the radiation is doubled, then Einstein's photoelectric equation changed as

K' = h(2v) - W₀    ...(ii)

By substracting the Eq. (i) from (ii), we get

K' - K = h(2v) - hv - W₀ + W₀

⇒ K' = K + hv