How is the resistance of a wire affected, if 1. Its length is doubled.2. Its radius is doubled.

How is the resistance of a wire affected, if 1. Its length is doubled.

1.	How is the resistance of a wire affected, if 1. Its length is doubled.2. Its radius is doubled.
Answer» (a) Resistance of a wire is directly proportional to the length of a wire; so if the length is doubled, resistance is also doubled.(b) Resistance of a wire is inversely proportional to the area of cross-section the wire. Thus, if radius is doubled, area increases four times and hence the resistance becomes one-fourth.