Lesson: Resistance and Resitivity of Conductors

A wire made of an unknown substance has a resistance of 125 mΩ. The wire has a length of 1.8 m and a cross-sectional area of m². What is the resistivity of the substance from which the wire is made?

A copper wire with a resistance of 12.8 mΩ has a cross-sectional area of m. Find the length of the wire. Use Ω⋅m for the resistivity of copper.

Which of the following statements correctly states how the resistivities of the sections of conducting wire in diagram (a) and diagram (b) compare to each other?

Which of the following statements correctly states how the cross-sectional areas of the conducting wires compare to each other?

Which of the following statements correctly states how the average time taken for a free electron to cross from one side of the section to the other side in diagram (a) compares to the average time taken for a free electron to cross from one side of the section to the other side in diagram (b)?

Which of the following statements correctly states how the resistance of the section of conducting wire in diagram (a) compares to the resistance of the section of conducting wire in diagram (b)?