Which is a correct closed circuit?
ABulb connected to a single wire ending in space
BCell with key open, wires hanging in air, bulb separate
CCell, key (closed), connecting wires, bulb, return to cell
DCell with one terminal connected to the bulb only
Answer & Solution
Correct answer: C. Cell, key (closed), connecting wires, bulb, return to cell
1. A current flows only when the circuit is a complete loop.
2. Cell, closed key, connecting wires, bulb and a return path form a loop.
3. Any break (open key, dangling wire) stops the flow.
4. So option A is the correct closed circuit.
_Source: Selina Concise Physics Class 9, Ch 9 Current Electricity (Mistral OCR'd PDF), section on closed and open circuit_
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