Current Electricity - Result Question 49
52. 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:
[2009]
(a) $-r$ and $E$
(b) $r$ and $-E$
(c) $-E$ and $r$
(d) E and $-r$
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Answer:
Correct Answer: 52. (a)
Solution:
- (a) The terminal potential difference of a cell is given by $V+Ir=E$
$\Rightarrow \frac{dV}{dI}=-r, \quad$ Also for, $i=0$ then $V=E$
$\therefore \quad$ slope $=-r$, intercept $=E$
