Question

Free electrons, generally, are not able to leave the metallic surface because

• A. they are very strongly held by the nucleus
• B. they do not have sufficient energy
• C. they require extremely large amounts of energy to be emitted
• D. they form a magnetic net that is difficult to pass through

Answer 1

The correct option is B

they do not have sufficient energy

Free electrons are generally not able to leave the metallic surface because they do not have sufficient energy to do so. They require a minimum energy equal to their Thermionic work function to leave the surface of the metal.