Question

a) Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.5 mm. Conductor B is a hollow tube of outside diameter 4.1 mm and inside diameter 2.9 mm. What is the resistance ratio R_A/R_B, measured between their ends?

b)In the figure current is set up through a truncated right circular cone of resistivity 735 Ω·m, left radius a = 2.17 mm, right radius b = 2.42 mm, and length L = 1.95 cm. Assume that the current density is uniform across any cross section taken perpendicular to the length. What is the resistance of the cone?

Please show all work, I'm not sure what I'm doing wrong.

Answer 1