What do you mean by work function of metal ?

Explanation

### Step-by-Step Solution:

1. **Definition of Work Function**: The work function of a metal, denoted by the symbol \( \phi \), is defined as the minimum energy required to remove an electron from the surface of the metal. This concept is crucial in understanding the photoelectric effect.

2. **Relation to Photoelectric Effect**: The work function is directly related to the photoelectric effect, which occurs when light of a certain frequency strikes a metal surface and causes the emission of electrons. If the energy of the incoming photons (light particles) is greater than the work function, electrons can be emitted.

3. **Threshold Frequency**: The work function is associated with a specific frequency of light known as the threshold frequency (\( \nu_0 \)). This is the minimum frequency of light required to emit electrons from the metal surface. The relationship can be expressed as:
\[
...