Question

Which of the following is the correct statement regarding resistance?

a. the resistance of a wire is inversely proportional to the resistivity of the wire

b. the resistance of a wire is directly proportional to the length of the wire

c. the resistance of a wire is directly proportional to the area of the wire

d. all of the above statements are correct

e. none of the above statements are correct

Consider two copper wires. One wire has twice the length of the other wire. How do the resistivites of these two wires compare?

a. Both wires have the same resistivity

b. The longer wire has twice the resistivity as the shorter wire

c. The longer wire has four times the resistivity as the shorter wire

d. the shorter wire has twice the resistivity as the longer wire

e. The shorter wire has four times the resistivity as the longer wire

Answer 1

1) Ans.  the resistance of a wire is directly proportional to the length of the wire

and directly proportional to resistivity and inversely proportional to the area of cross section.

2. ans) Both wires have the same resistivity

resistivity is the resistance per unit length and area, of a particular material and its constant.