Question

In the photoelectric experiment, the frequency of the incident radiation is double(D) What will be its effect on the photoelectric current?

• A. Photoelectric current will be halved
• B. Photoelectric current will be doubled
• C. Photoelectric current will not change
• D. Photoelectric current will become zero

Hint:

The photoelectric current is proportional to the intensity of the incident light (number of photons), not its frequency. Doubling the frequency increases the energy of the photoelectrons but does not change the current.

Answer 1

The Correct Option is C

In the photoelectric effect, the photoelectric current is determined by the number of photoelectrons emitted from the surface of the material. The current is directly proportional to the number of photoelectrons emitte(D) The number of emitted photoelectrons depends on the intensity of the incident light, not its frequency. The formula for the photoelectric effect is given by: \[ E_{\text{photon}} = h \cdot f \] Where: - \( E_{\text{photon}} \) is the energy of a photon, - \( h \) is Planck's constant, - \( f \) is the frequency of the incident radiation. When the frequency is doubled, the energy of the individual photons also increases, but it does not affect the number of photons hitting the surface. For the emission of photoelectrons, the energy of the photons must be greater than the work function \( \phi \) of the material. If the frequency of light is already above the threshold frequency, doubling the frequency will result in photons with more energy, but it will not change the number of photons striking the surface. The photoelectric current depends on the number of emitted electrons, which is influenced by the intensity of the light (i.e., the number of photons per second) rather than the frequency. Doubling the frequency only increases the energy of the emitted electrons, not their number. Thus, the photoelectric current will not change because the number of emitted electrons (which determines the current) remains the same. Therefore, the correct answer is Option (C): "Photoelectric current will not change."