Question

If the length and radius of a conductor
are both halved, the resistance becomes
1) doubled 2) 4 times
3) halved
4) doesn't change​

Answer 1

Explanation:

$R =p\frac{L}{πr^2}$

$when,$

$L =\frac{L}{2} , r =\frac{r}{2}$

$then ,$

$R' =p\frac{\frac{L}{2}}{\frac{πr^2}{4}}$

$R' =p\frac{4L}{2πr^2}$

$R' =p\frac{2L}{πr^2}$

$R' =2p\frac{L}{πr^2}$

$R' = 2R$

$Resistance \: will \: become \: doubled.$