2L 2L 4L 2r 2r 2r 1 2 3 4 FIGURE Q22.10

A material of resistivity p is formed into a solid, truncated cone of height h and radii r₁ and r2 at either end. Calculate the resistance of the cone between the two flat end faces.

Pure copper has a resistivity of 1.68 × 10−8 Ωm. Some accurate cubes of copper are prepared,and electrical measurements are made, for which current is passed across a pair of oppositefaces.a) Comparing a 2.5 cm cube and a 5 cm cube, which will have the higher conductance? Explain your answer.b) Given eight 1 cm cubes, how can they be stacked to get the highest and the lowest resistance between opposite faces of the stack? Calculate the resistance of each stack.

Aluminum and copper wires of equal length are found to have the same resistance. What is the ratio of their radii? Note: You need to use the concept of resistivity and find the resistivity of these two materials to solve this problem. You can find a table of resistivity in your textbook or use the internet.