Question

Define threshold frequency.

Answer 1

Hint: Whenever a photon beam strikes a metal surface, electrons are emitted from the metal surface, but these electrons are not emitted as soon as the electrons strike, it actually relies on a variety of factors, one of which is the frequency of the threshold. To approach the solution, use this conception.

Complete solution:
1.Threshold frequency: The threshold frequency is the minimum frequency below which photoelectric incident radiation occurs.
2.Emission, irrespective of the intensity of the incident radiation, is not possible.
3.Photoelectric impact: Photoelectric effect is the emission of electrons when the material such as any metal part) is affected by a ray of light coming from the source such as SUN (i.e. electromagnetic radiation coming from the SUN). Emitted electrons are referred to as photoelectrons.
4.Thus, the frequency of the threshold is the frequency of light that carries enough energy to dislodge an electron from an atom (i.e. to release an electron from the metal containing electrons in a resting position, each metal containing electrons).
5.Therefore, if the frequency of the incident radiation is less than the frequency threshold of the metal, no electrons have been released from the metal because electrons do not acquire kinetic energy or do not acquire enough kinetic energy to dislodge an electron from the atom or metal part.
6.Since the electrons do not obtain sufficient velocity to obtain sufficient kinetic energy, kinetic energy (K.E) is half the mass (m) multiplied by the velocity (v) square of the electrons.
$K . E=\dfrac{1}{2} m v^{2}$

So, this is the required answer.

Note:
When a wave of light hits a metal surface, the main reason behind the emission of electrons from the metal surface is due to the dual behavior of light, since light can act as both wave and particle, so this illustrates that light consists of photons or energy quanta. When the surface is hit, these photons transfer energy to the surface electrons and thus make the emission possible.