Define ‘quality factor’ of resonance in series LCR circuit. What is its SI unit?

Explanation

### Step-by-Step Solution:

1. **Definition of Quality Factor (Q)**:
The quality factor (Q) of resonance in a series LCR (Inductor-Capacitor-Resistor) circuit is a dimensionless parameter that describes how underdamped an oscillator is. It characterizes the bandwidth of the resonator relative to its resonant frequency.

2. **Understanding Quality Factor**:
The quality factor indicates how sharp or selective the resonance is. A higher Q value signifies a sharper resonance peak, meaning the circuit can oscillate at a narrow range of frequencies around the resonant frequency.

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