Question

The current-voltage graph for a given men. wire at two different temperatures $T_{1}$ and $T_{2}$ are shown in given figure, which of the relation is correct from the following?

• A. $T_{2} > T_{1}$
• B. $T_{1} > T_{2}$
• C. $T_{1}=T_{2}$
• D. None of these

Answer 1

Answer: (A)

From Ohm's law $V = IR$
$\Rightarrow \frac{I}{V} = \frac{1}{R}$
Hence, slope $=\frac{1}{R}$
Since slope of graph at temperature $T_{1}$ is greater than that at temperature $T_{2}$, so $R_{1} < R_{2}$. Since, resistance increases with rise of temperature.
Hence, $T_{2}>T_{1}$