A 6 V battery of negligible internal resistance is connected in series to a fixed resistor of 2 ohm and a 1 metre resistance wire of 4 ohms. A cell of e.m.f E of internal resistance 0.5 ohm shows a balance length of 0.500m . What is the emf E?
Mental workout:
1. Pd across resistance wire of 1m is 4V.
2. If 1 m is 4 V , 0.5 m will give 2 V.
3. The emf E is 2 V .
note: The internal resistance of 0.5 ohm has no pd across it as no current is flowing through it.
