Question

As the intensity of incident light increases
A. Kinetic energy of emitted photoelectrons increase
B. photoelectric current decreases
C. photoelectric current increases
D. kinetic energy of emitted photoelectrons decreases

Answer 1

Hint: When light is made to fall on the surface of a metal, the electrons are ejected from the surface of the metal. These ejected electrons are also called photoelectrons.

Complete step by step solution:
The number of electrons that are ejected from the surface of metal depends on the frequency of the light incident on the surface of the metal and also the kinetic energy with which light is travelling. In the photoelectric effect, intensity is defined as the number of electrons ejected from the metal surface per unit of time.

If in the photoelectric effect, the intensity of incident light is increased on the metal surface, the number of photons or the amount of energy striking on the surface of the metal will also increase, hence increasing more electrons from the metal surface. As a result, the photoelectric effect will increase. Therefore, as the intensity of incident light increases, the photoelectric current will also increase.

Hence, Option C is the correct answer.

Note:In the photoelectric effect, the electrons on the surface of the metal surface absorb energy when light is incident on the metal surface. The photons of the light that is being incident on the metal surface, should possess a minimum amount of energy to remove the electrons from the metal surface. This minimum energy is known as threshold energy. If the energy of incident light is less than the threshold energy, no electrons will be emitted. Since different types of metals have different attractive forces that bind electrons to the nucleus, therefore, threshold energy will be different for different metals.