Important Formulae for Photoelectric Effect:

The photoelectric effect refers to the phenomenon where light incident on a material surface causes the emission of electrons. It can be explained using various formulae that describe the relationship between the different parameters involved. Here are some important formulae for the photoelectric effect:

1. Einstein's Photoelectric Equation:
The photoelectric effect can be understood using Einstein's photoelectric equation, which relates the energy of incident photons to the maximum kinetic energy of emitted electrons:

E = hf = W + K.E.

Where:
- E represents the energy of the incident photon.
- h is Planck's constant (h = 6.626 x 10^-34 Js).
- f is the frequency of the incident light.
- W is the work function of the material (minimum energy required to remove an electron from the surface).
- K.E. is the maximum kinetic energy of the emitted electron.

2. Kinetic Energy of Emitted Electrons:
The maximum kinetic energy of emitted electrons can be calculated using the equation:

K.E. = hf - W

Where:
- K.E. represents the maximum kinetic energy of the emitted electron.
- h is Planck's constant.
- f is the frequency of the incident light.
- W is the work function of the material.

3. De Broglie's Wavelength:
The wavelength of a particle, such as an electron, can be calculated using De Broglie's equation:

λ = h / p

Where:
- λ represents the wavelength of the particle.
- h is Planck's constant.
- p is the momentum of the particle.

4. Stopping Potential:
The stopping potential is the minimum potential required to stop the emission of electrons. It can be calculated using the equation:

V0 = (hf - W) / e

Where:
- V0 represents the stopping potential.
- h is Planck's constant.
- f is the frequency of the incident light.
- W is the work function of the material.
- e is the elementary charge (e = 1.6 x 10^-19 C).

5. Threshold Frequency:
The threshold frequency is the minimum frequency of light required to cause the photoelectric effect. It can be calculated using the equation:

f0 = W / h

Where:
- f0 represents the threshold frequency.
- W is the work function of the material.
- h is Planck's constant.

These formulae are essential in understanding and quantifying the photoelectric effect. They help to explain the relationship between the energy of incident photons, work function, maximum kinetic energy of emitted electrons, and other important parameters.