Question

A particular resistance wire has a resistance of 3 ohm per metre. Find the resistance of 5 m length of a wire of the same material but with twice the area of cross section

Answer 1

Answer:

1.5 ohm

Explanation:

material is same so resistivity is equal

using formula,

r=rho×l/A

3=l/A. --eqn 1

for second wire resistance is R area of cross section is double

R=l/2A. --eqn 2

putting value of l/A eqn 1 in eqn 2,

we get ,

R=3/2

=1.5 ohm