When a metal is heated to a high temperature, electrons are emitted from its surface. The process is known as
A
photoelectric effect
B
thermionic emission
C
field emission
D
secondary emission
E
radioactive emission
Verified Correct Answer: B.
Physical Principles & Numerical Solution
The process by which free electrons are emitted from the surface of a metal when external heat energy is applied is called thermionic emission.
Source: Myschool Past Questions Archive (Record #42683)