Question

A conductor of length 65 cm has a resistance of 4ohm. Calculate the resistance of a same conductor
of length 260 cm.
(Ans. 16 ohm)​

Answer 1

$\bold{⇒R = \dfrac{ρl}{A}}$

$\bold{ ⇒R ∝ l}$

$\bold{⇒\dfrac{R_{1}}{R_{2}} ∝ \dfrac{l_{1}}{l_{2}}}$

$\bold{⇒\dfrac{4}{R_{2}} = \dfrac{65}{260}}$

$\bold{⇒R_{2}=\dfrac{260×4}{65}}$

$\bold{⇒R_{2}=16 ohm}$

Answer 2

Explanation:

R2 = 16 ohm. So the conductor of length 260cm will give resistance of 16ohm. This is because length ∝ is to the resistance given by the conductor.