Question

When do electrons escape from a heated metal in thermionic emission?

विकल्प

• When some electrons gain enough energy to overcome the work function

• Only when light of suitable frequency falls on the metal

• Whenever free electrons move inside the metal

• When surface positive ions pull electrons inward

Answer 1

Heating supplies thermal energy, but escape requires enough energy to overcome the work function. Electrons that do not gain enough energy remain inside.