EMF of a cell is defined as:
AWork done per unit charge by the source
BVoltage drop across internal resistance
CCurrent per unit charge moved by source
DPower dissipated by source per second
Answer & Solution
Correct answer: A. Work done per unit charge by the source
1. EMF ε is the work the source does per coulomb of charge moved around the circuit (or measured open-circuit terminal voltage).
2. Even with no current, the cell maintains ε across its terminals.
3. SI unit: volt (J/C).
_Source: NCERT Class 12 Physics Ch 3 §3.8 EMF Definition_
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