Question

$I-V$ characteristic of a copper wire of length $L$ and area of cross-section $A$ is shown in figure. The slope of the curve becomes

• A. More if experiment is performed at higher temperature
• B. More if a wire of steel of same dimension is used
• C. Less if the area of the wire is increased
• D. Less if the length of the wire is increased

Answer 1

Answer: (D)

Slope $=1/R=A/\rho l$
Hence the slope becomes less if the length of the wire is increased.