NEETPhysicsCurrent Electricity
A circuit consists of a single loop containing two cells and an external resistor of 3 . The first cell has an EMF of 10 V and an internal resistance of 2 . The second cell has an EMF of 4 V and an internal resistance of 1 . If the cells are connected such that their polarities oppose each other, what is the terminal potential difference across the 4 V cell?
Options
- A5 V
- B3 V
- C4 V
- D8 V
Correct answer
A. 5 V
Step-by-step solution
The two cells are connected in series but oppose each other. The net EMF of the circuit is the difference between their EMFs: E_ net = 10 V - 4 V = 6 V The total resistance of the circuit includes the external resistor and the internal resistances of both cells: R_ total = 3 + 2 + 1 = 6 The current I flowing through the circuit is: I = E_ net R_ total = 6 6 = 1 A Since the 10 V cell is stronger, it dictates the direction of the current. The current enters the positive terminal of the 4 V cell, meaning this weaker c