NEETPhysicsCurrent Electricity
The variation of terminal potential difference ( V ) with current ( i ) drawn from a cell is a straight line with a negative slope. If the graph intersects the V -axis at 10 ~V and the i -axis at 5 ~A , what will be the terminal potential difference of the cell when a current of 2 ~A is drawn from it?
Options
- A14 ~V
- B10 ~V
- C4 ~V
- D6 ~V
Correct answer
D. 6 ~V
Step-by-step solution
The equation for the terminal potential difference of a discharging cell is V = E - ir . The V -intercept (where i = 0 ) gives the emf of the cell: E = 10 ~V The i -intercept (where V = 0 ) gives the short-circuit current: 0 = E - i_ sc r i_ sc = E r = 5 ~A The internal resistance r is: r = 10 5 = 2 When a current of 2 ~A is drawn, the terminal potential difference is: V = E - ir = 10 - (2 2) = 6 ~V Answer: 6 ~V