Question

A pice of wire resistance 20ohm is drawn out so that it's length is increased to twice it's original length. calculate the resistance of the wire in the new situation
$\huge{\bold{\underline{\red{Solve\:It}}}}$​

Answer 1

$\huge{\bold{\underline{\red{SolutioN:}}}}$

The length of a piece of wire is doubles. So, length of wire is $2l$.

To find the resistance of the wire = ?

We know that,

$\qquad \sf Area\:of\:cross\:sectional\: = \: \dfrac{A}{2}$

$\quad \quad : \implies \sf Resistance, R = \dfrac{\rho l}{A} = 20$

$\qquad \quad : \implies \sf R' = \dfrac{\rho l}{A}$

$\qquad \quad : \implies \sf \rho (2l) \times \dfrac{2}{A}$

$\qquad \qquad : \implies \sf \dfrac{4 \rho l}{A}$

$\qquad \quad : \implies \sf 4 \bigg( \dfrac{\rho l}{A} \bigg)$

$\qquad \qquad : \implies \sf 80 ohm$

Therefore,

The resistance of the wire is 80 ohm.

Answer 2

Answer:

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