Electrons are emitted from a conductor when the conductor is

A. bombarded by high-speed electrons.

B. cooled rapidly.

C. subjected to a small voltage.

D. exposed to weak light.

A. bombarded by high-speed electrons.

Electrons are emitted from a conductor when the conductor is bombarded by high-speed electrons. This is because the electrons that are already present in the object especially when the object receiver is a metal, water or any object able to conduce electricity, the electrons in these objects are in form of potential energy and when other electrons are in contact with them they move and thus being from potential to kinetic.