A section of wire 10.0 m long has a resistance of 4.00 O. (a) What is the resistance of 25.0 m of this wire? (b) What is the resistance of a 10.0 m section of wire of the same material with half the diameter? (c) What is the resistance of a wire whose length is 20.0 m and diameter is twice as large as the wire in part a?
The answers in the book are
(a) 10.0 O
(b) 16.0 O
(c) 2.00 O
Please explain how to get these answers.