Question

A wire with a resistance of 20 ohm is drawn out so that it's length becomes thrice it's original length. The new resistance is :

Answer 1

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

→ Given : A wire with a resistance of 20 ohm is drawn out so that it's length becomes thrice it's original length. The new resistance is ?

→ Answer : The new resistance is R = 60 $\Omega$

→ Formula :  $\frac{R_1}{R_2}=\frac{l_1}{l_2}$

→ Explanation :

Relation between Resistance and length of wires are   $\frac{R_1}{R_2}=\frac{l_1}{l_2}$.

A Resistance , $R_1=20\Omega$

Let , Length , $l_1=lm$

It's length becomes thrice it's original length

So Length , $l_2=3lm$

New Resistance , $R_2=?$

$=>\frac{R_1}{R_2}=\frac{l_1}{l_2}\\\\ =>\frac{20}{R_2} =\frac{l}{3l}\\\\ =>R_2=60\Omega$

↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑

>>> Hope Helps You <<<