`I-V` characteristics of a copper wire of length `L` and area fo cross-section `A` is shown in Fig. The slope of the curve becomes

Options

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

Answer

D

Explanation

Slope of V-I curve `=R = (rho l)/A`
Slope of I-V curve = `1/R = A/(rho l)`
as `I uarr`, slope decreases.