Question

Question 10
A cylindrical conductor of length l and uniform area of cross-section A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross section

(a) $\frac{A}{2}$
(b) $\frac{3A}{2}$
(c) $2A$
(d) $3A$​​​​​​​

Answer 1

(c) $2A$

The electrical resistivity $\rho$ is defined as:
$\rho =R\frac{A}{l}$
Where,
R is the electrical resistance of a uniform specimen of the material, l is the length of the piece of material and A is the cross - sectional area of the specimen.
To keep the resistance same, if we double the length, we have to double the area also.