Question

Calculate the resistance of 2 kilometre long copper wire of radius 2 millimetre (resistivity of copper equal to 1.72 into 10 ^ - 8

Answer 1

Answer:

convert the 2km into 2000 m

convert the 2 mm into 0.002 m

now R=P(L/A)

SUBSTITUTING the values

1.72×10^-8(2000/3.14×(0.002)^2)

we will get

1.72×10^-8(2000/3.14×0.000004)

1.72×10^-8(2000/0.00001256)

=273885350.318×10^-8 ohms

if we simplify this further, we will get

2.73885350318 ohms

you can write upto 2 decimal places

so, 2.73 ohms

Explanation:

273885350×10^-8ohms

2.73ohms

both are correct

you can write by the advice of your teacher to the further simplification