Two cells are connected between points A and B as shown. Cell 1 has emf of 12 V and internal resistance of 3 Ω . Cell 2 has emf of 6 V and internal resistance of 6 Ω . An external resistor R of 4 Ω is connected across A and B . The current flowing through R will be ______ A .

Step-by-step solution

Equivalent internal resistance of two cells in parallel is r e q = r 1 r 2 r 1 + r 2 = 3 × 6 3 + 6 = 2   Ω Equivalent emf of given cells E e q = E 1 r 1 - E 2 r 2 r e q = 12 3 - 6 6 2 = 6   V Given: R = 4   Ω The circuit can be redrawn as shown below. Current through resistor R is I = 6 2 + 4 = 1   A .