Question

calculate the resistance of an aluminum cable of length 10km and diameter 2.0 mm if the resistivity of aluminum is 2.7X 10_8 ohm metre

Answer 1

Refer to the attachment.

Answer 2

We know that ,
R = rl ÷A

here,
R => resistance
r => resistivity
l => length
A => area
Because the length is given in km we will change it into m .
And diameter is given and we will find radius
and here also diameter is given in mm so we will convert it into metre by multiplying it by 10 ^-3 and we will first find area of it by
$\pi {r}^{2}$
so we will get A = 1× 10 ^-6 × 3.14

Then,

R = 2.7× 10^-8 × 10000 ÷ 1 × 10^-6 × 3.14
= 2.7 × 10^-4 ÷ 3.14 × 10^-6
= 85.94
= 86 ohm (approx)


HØPĖ İŤ HĒŁPŠ