State the characteristics of photoelectric effect

Explanation

### Step-by-Step Solution:

1. **Definition of Photoelectric Effect**:
The photoelectric effect refers to the phenomenon where electrons are emitted from a metal surface when it is exposed to electromagnetic radiation (light). This effect demonstrates the particle nature of light.

2. **Threshold Frequency**:
For the photoelectric effect to occur, the incident radiation must have a minimum frequency known as the threshold frequency (ν₀). If the frequency of the incident light is below this threshold, no electrons will be emitted, regardless of the intensity of the light.

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