Question

The resistance of a straight conductor does not depend on its

• A. length
• B. temperature
• C. material
• D. shape of cross-section

Answer 1

Answer: (D)

Resistance of a conductor
$R=\frac{\rho l}{A}$ ...(i)
As $\rho$ depends on the material,
so R depends on the material.
According to the given formula in Eq.(i), it depends on length. Moreover resistance $\propto$ temperature.
If $R_0=$ resistance of conductor at $0^{\circ }C,$
$R_t=$ resistance of conductor at $t^{\circ }C$ ,
and $a,\beta =$ temperature coefficient of resistance, then
$R_t=R_0\left(1+\alpha t+\beta t^2\right)$
The resistance of a straight conductor does not depend on shape of cross-section.