Question

The photoelectric effect describes electrons being ejected from a metal. Assume that a wavelength of light has caused electrons to be emitted from a metal.

a. What would be observed if only the intensity of the light is increased?

b. What would be observed if only the frequency of the light was increased?

Answer 1

Photoelectric effect: When a light wave having smaller wavelength ( eg: Gamma ray ,X-ray ,UV ray etc) fall on a metal,there is emissions of electron.This emitted electron is called photoelectron and the current associated with it is called photoelectric current.And this phenomenon is called photoelectric effect.

a) Effect of intensity: As the intensity of light wave inreases,the value of photoelectric current also increases.The maximum kinetic energy of photoelectron does not depend upon intensity of light.

b) Effect of frequency: As the frequency of light wave increases ,the maximum kinetic energy of photoelectron also increases.The photoelectric current does not depend on frequency.