The process through which free electrons leave the surface of hot metal is known as?
A
photon emission
B
photo emission
C
thermionic emission
D
electron emission
Verified Correct Answer: C.
Physical Principles & Numerical Solution
This process occurs when the thermal energy of the metal is sufficient to allow electrons to overcome the work function and escape from the surface.
Source: Myschool Past Questions Archive (Record #13888)