A student measures the terminal potential difference (V)

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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:

1. – r and E
2. r and – E
3. – E and r
4. E and – r

Correct Option: A

The terminal potential difference of a cell is given by V + Ir = E
V = V_A – V_B
or V = E – Ir
⇒ dV/dI = -r,
Also for, i = 0 then V = E
∴slope = – r, intercept = E