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In a circuit, resistors of 2 ohm, 3 ohm and 4 ohm are connected in parallel across a battery of EMF 12 V and negligible internal resistance. Which resistor dissipates the maximum power?

1. 2 ohm resistor
2. 3 ohm resistor
3. 4 ohm resistor
4. All three resistors dissipate equal power

Correct answer: 2 ohm resistor

Solution

When resistors are connected in parallel, the voltage across each is equal to the supply voltage (12 V here). Power consumed by each resistor is P = V² / R. Therefore P is inversely proportional to R, so the resistor with the smallest resistance dissipates the maximum power.

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