`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 increased
D. Less if the length of the wire is increased

Answer

D

Explanation

(d) Slope of `V-i` curve `= R(=(rho l)/(A))`. But in given curve axis of `i` and `V` are interchanged. So slope of given curve
`= (1)/(R ) (=(A)/(rho l))` i.e., with the increase in length of the wire. Slope of the curve will decrease.