Question

A wire of length of 10 cm has a resistance 4 ohm. if the wire is stretched to double it's length find its new resistance?​

Answer 1

Answer:

$resistance \: is \: directly \: proportional \: to \: length$

$\frac{r1}{r2} = \frac{l1}{l2}$

$\frac{4}{r1} = \frac{10}{20}$

$10 \times r1 = 80$

$r1 = 8ohm$