A student measures the terminal potential difference (V) of a cell (of emf E and internal resistance r) as a function of the current (I) flowing through it. The slope and intercept, of the graph between V and I, then, respectively, equal:

Options

(a) – r and E
(b) r and – E
(c) – E and r
(d) E and -r

Correct Answer:

– r and E

Explanation:

The terminal potential difference of ao ocell is given by V + Ir = E V = Vₘ – Vₙ
or V= E – Ir
dV/ dI = – r, Also for i= 0 then V = E
slope = – r, intercept = E