Question

A wire of given material having length L and area of cross section A has resistance 8ohm. What would be the resistance of another wire of same material, length 4L and area A/2

Answer 1

Answer:

Since the two wires are made up of same material their resistivity will be same so,

8×A/l=R/4l×A/2

or, 8=R/8

or, R=64ohm

Answer 2

Answer:

64Ω

Explanation:

Since the two wires are made up of same material their resistivity will be same

ρ = RA/l

8×A/l=$\frac{RA}{2}$×$\frac{1}{4L}$

8=R/8 (cutting off A/L on both sides)

R=64Ω