Question

How do the length and cross section area of a conductor affect its resistance of a conductor changes when: i. Length is get half; ii. Radius of wire is doubled?

Answer 1

1.when length is getting half the resistance of conductor becomes 1/4

2.when radius of wire is doubled it becomes 1/16times

3.since formula for resistance is Rα l/a

RαL/πr²

THEREFORE

R1/R2=l1/r1²×l2/r2²

l1/l2=r2/r1

4.since volume of wire before stretching and after stretching are equal

5.therefore when radius is getting doubled since it is inversely proportional to fourth power of radius  it becomes 1/16 times of the original resistance

and

6.when length is half resistance will become 1/4

Answer 2

Answer:

both cases resistivity decreases

Explanation: