Question

Why were electrons coming out from a metal when it was kept under a light source?

• A. Light is an EM wave so when it falls on the metal surface its electric field pulls the electrons towards the source of light
• B. Light is a form of energy. The free electrons in the metal when get sufficient energy from light, they jump out of the metal
• C. Light has negative charge. When it falls on an electron it makes it more negatively charged and they jump out of the metal by repelling other electrons.
• D. God told electrons "Thou shalt leave the metal, whenever light falls unto thee" and so they come out

Answer 1

The correct option is B

Light is a form of energy. The free electrons in the metal when get sufficient energy from light, they jump out of the metal

Free electrons are free to move but only within the boundaries of a metal, they are still attracted by not one but many atoms, so they cannot leave the metal surface.

Light is a form of energy. When it falls on an electron it transfers its energy to it. The free electrons in the metal, when they get the required energy to leave, they jump out of the metal.