NEETPhysicsCurrent Electricity
A cell of emf 6 ~V and internal resistance 1 is connected across a parallel combination of two identical external resistors of 4 each. The terminal potential difference of the cell is:
Options
- A4 ~V
- B5.33 ~V
- C6 ~V
- D2 ~V
Correct answer
A. 4 ~V
Step-by-step solution
The equivalent resistance of the two 4 resistors in parallel is: R_ eq = 4 4 4 + 4 = 2 The total resistance of the circuit, including the internal resistance r , is: R_ total = R_ eq + r = 2 + 1 = 3 The current drawn from the cell is: i = E R_ total = 6 3 = 2 ~A The terminal potential difference V across the cell is the voltage across the equivalent external resistance: V = i R_ eq = 2 2 = 4 ~V Alternatively, using the cell formula: V = E - ir = 6 - (2 1) = 4 ~V Answer: 4 ~V