If the intensity and frequency of incident light is doubled then :

The correct answer is option 2) i.e. the kinetic energy of the emitted electron will be increased and the photoelectric current will be 2 times.

CONCEPT:

• Photoelectric effect: The photoelectric effect is a phenomenon where electrons are ejected from a metal surface when the light of sufficient frequency is incident on it.
  • ​Einstein suggested that light behaved like a particle and that each particle of light had energy called the photon.
  • When a photon falls on the metal surface, the photon’s energy is transferred to the electron.
  • Some part of the energy gets utilized in removing the electron from the metal surface, and the remaining goes into giving kinetic energy for the ejected electron.

Therefore, the total energy of photon = energy utilized to eject an electron + maximum kinetic energy of the electron.

The energy of a photon is given by the equation:

 \(E =hν\). Where ν is the frequency of incident light and h is the Planck's constant.

​Where E is the energy of the photon, W is the minimum energy required to emit an electron, and KE is the maximum kinetic energy achieved by the ejected electron.

EXPLANATION:

• The intensity of light refers to the amount of photon energy per unit area. 
  • So, the greater the intensity of light more will be the number of photons, and as a result, more will be the number of ejected electrons. More electrons constitute more photocurrent.
  • So if the intensity is doubled, the photocurrent also gets doubled.
• ​The photocurrent is independent of the frequency of incident light.
• The energy of a photon is directly proportional to the frequency of incident light. So if the frequency is doubled, The energy is also doubled. Hence, more amount of kinetic energy is available for the emitted electrons.

​∴ the kinetic energy of the emitted electron will be increased and the photoelectric current will be 2 times.