In the circuit shown for verifying Ohm's law, suppose the path is broken by opening the key. What is the immediate consequence in an ideal circuit? 
ACurrent continues to flow because the battery is connected
BOnly the voltmeter current increases
CNo current flows through the conductor because the circuit is no longer closed
DThe resistance of the conductor becomes zero
Answer & Solution
Correct answer: C. No current flows through the conductor because the circuit is no longer closed
An electric circuit must be a closed and continuous path for current to flow. Opening the key breaks that path, so the circuit becomes incomplete and current through the conductor stops. The battery alone cannot maintain current in an open circuit.
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