Question

According to Einstein’s model minimum energy needed for the electron to escape from a metal surface having work function ϕ₀, the electron is emitted with maximum kinetic energy, K_max = ______.

Options

• `"h"nu + phi_0`

• `"h"nu`

• `"h"nu - 2 phi_0`

• `"h"nu - phi_0`

Answer 1

According to Einstein’s model minimum energy needed for the electron to escape from a metal surface having work function ϕ₀, the electron is emitted with maximum kinetic energy, K_max = `underline("h"nu - phi_0)`.

Explanation:

When a photon collides with a metal surface, the complete energy of the photon is transferred to an electron. Some energy (Work Function) is expended in coming out of the metal surface, and the remaining energy is electron kinetic energy.

E = `phi_0 + "K"_"max"`

`"K"_"max" = "E" - phi_0`

`"K"_"max" = "h"nu - phi_0`