Question

Write the experiment observation of photo electric effect

Answer 1

1. Existence of threshold frequency

For a given metal, no photoelectrons are emitted if the frequency of the incident light is lower than a certain frequency. If the light frequency is below this threshold frequency for that metal, no photoelectrons can be emitted, no matter the intensity of the incident radiation is or for how long it falls on the surface of the metal.

2. Emission is instantaneous

Emission of photoelectrons takes place almost instantaneously after the light shines on the metal, with no detectable time delay. It does not depend on the intensity of the incident radiation.

3. Maximum Kinetic Energy of the photoelectron is independent of intensity of incident electromagnetic radiation

Photoelectrons emitted from a metal have a range of velocities from zero up to a maximum VmaxVmax. The maximum kinetic energy 12mV2max12mVmax2 was found to depend linearly on the frequency of the radiation and is independent of its intensity.

4. Rate of emission of photoelectrons proportional to intensity of incident electromagnetic radiation