Why a spark is produced in a switch sometimes when it is switched off?

Explanation

### Step-by-Step Solution

1. **Understanding the Circuit**: When a switch is in the "on" position, it completes the circuit, allowing current to flow. When the switch is turned "off," it breaks the circuit, stopping the flow of current.

2. **Sudden Interruption of Current**: The act of turning off the switch causes a sudden interruption in the current flow. This rapid change can lead to a phenomenon known as electromagnetic induction.

3. **Induction of EMF**: According to Faraday's law of electromagnetic induction, a change in current can induce an electromotive force (EMF) in the circuit. When the switch is turned off, the sudden decrease in current creates a large induced EMF across the gap of the switch.

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