What is photoelectric effect?

The photoelectric effect is a phenomenon in physics. Here's a step-by-step explanation:

1. The photoelectric effect is the observation that many metals emit electrons when light shines upon them.

2. This effect was first observed by Heinrich Hertz in 1887.

3. The electrons emitted in this manner can be called photoelectrons.

4. In the photoelectric effect, a photon (a particle of light) hits an atom and is absorbed by an electron in the atom.

5. This gives the electron enough energy to be 'knocked' out of the atom and become a free electron.

6. The energy of the emitted electron does not depend on the intensity of the incoming light but on the frequency of the light. This means that increasing the intensity of light increases the number of photoelectrons emitted but not their energy.

7. This phenomenon cannot be explained by classical physics and was one of the first direct evidences of quantum mechanics.

8. Albert Einstein won the Nobel Prize in Physics in 1921 for his explanation of the photoelectric effect.