Consider a long straight conducting wire that terminates in a metal sphere of radius r = 0.50 ± 0.01 cm. Suppose the wire is carrying a current of / = 3.0 ± 0.2 A in order to charge the sphere (positively).
(a) Sketch the shape of the electric and magnetic fields around the wire and the sphere.
(b) Discuss the relative merits of using the Biot-Savart law and Ampere's law to calculate the magnetic field around the wire. In this case, is it necessary to include the Maxwell correction to Ampere's law?
(c) Calculate the magnetic field strength at point P. which lies a distance of d = 1.00 ± 0.01 cm from the wire and I? = 10.0 ± 0.1 cm from the centre of the ball.
(d) Calculate the uncertainty in the magnetic field strength. Does the fact that this wire is not infinite in extent make a significant impact on the results? Explain.
