Question

In photoelectric effect, the photo current:

• A. increases with increase of the frequency of incident photon
• B. does not depend on the frequency of photon but depends only on intensity of incident light
• C. decreases with increase of frequency of incident photon
• D. depends both on intensity and frequency of incident beam

Answer 1

The correct option is B

does not depend on the frequency of photon but depends only on intensity of incident light

Explanation for correct option: Option B

1. When electromagnetic radiation hits a material, some electrons are emitted from it. This phenomenon is known as the photoelectric effect.
2. The current that flows through a material due to the photoelectric effect is known as the photoelectric current.
3. A specific amount of energy is required to liberate an electron from a metal surface, known as the work function of the metal.
4. When the intensity of the incident photon increases, the number of electrons emitted from the metal surface increases. This results in an increase in the photoelectric current. Mathematically it is given as $Photoelectriccurrent\propto Intensityoflight$. Thus, photoelectric current depends upon the intensity of light.
5. The frequency of the electrons has no effect on photoelectric current and is only related to the kinetic energy. It can be mathematically expressed as $KE=h\nu -\varphi$, where $KE$ is the kinetic energy, $h$ is Planck's constant a, $\nu$ is the frequency of incident photons and $\varphi$ is the work function of the metal.

Explanation for incorrect options:

Option A

Photoelectric current is independent of the frequency. So, this option is incorrect.

Option C

Photoelectric current is independent of the frequency. So, this option is incorrect.

Option D

The photoelectric current depends on intensity but is independent of the frequency. So, this option is incorrect.

Hence, the correct option is B.