In photoelectric effect, what is meant by the term .threshold frequency.?

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Threshold Frequency**: The term "threshold frequency" refers to the minimum frequency of incident light required to initiate the photoelectric effect.

2. **Photoelectric Effect Overview**: The photoelectric effect is the phenomenon where electrons are emitted from a material (usually a metal) when it is exposed to light of sufficient energy.

3. **Minimum Energy Requirement**: For electrons to be emitted from the surface of a metal, the incoming light must have a frequency that corresponds to a minimum energy level. This energy is needed to overcome the work function (the energy required to remove an electron from the surface of the metal).

...