An aluminum wire has a resistance of 7.00 ω at 30.0°c. determine its resistance (in ω) at 430°c. the temperature coefficient of resistivity for aluminum wire is 3.90 ✕ 10−3 (°c)−1. (assume that the temperature coefficient of resistivity was measured using the reference temperature 20°c.)

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c