A current of 3 A passes through an electric circuit for 5 minutes and does a work of 900J. What is the emf of the source?
Correct answer: B. 1V
- A. 3V
- B. 1V
- C. 5V
- D. 10V
Explanation
First, find the total charge that passed: Q = I × t = 3 A × (5 × 60 s) = 900 C. EMF (voltage) is defined as work done per unit charge: E = W / Q = 900 J / 900 C = 1 V.
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About Current Electricity
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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