Question

Under what condition does an electron escape after external energy is supplied?

Options

• No external energy is supplied.

• The supplied energy is greater than or equal to \[\phi_0\].

• The supplied energy is less than \[\phi_0\].

• The electron moves freely inside the metal.

Answer 1

An electron escapes if its supplied energy reaches or exceeds the work function \[\phi_0\]. The escape from the surface is electron emission.