Author Question: A long wire is known to have a radius greater than 4.0 mm and to carry a current uniformly ... (Read 43 times)

darbym82 · **on:** Jul 28, 2018

A long wire is known to have a radius greater than 4.0 mm and to carry a current uniformly distributed over its cross section. If the magnitude of the magnetic field is 0.285 mT at a point 4.0 mm from the axis of the wire and 0.200 mT at a point 10 mm from the axis, what is the radius of the wire?
a. 4.6 mm
b. 7.1 mm
c. 5.3 mm
d. 12 mm
e. 10 mm

Question 2

A long, straight wire (radius = 2.0 mm) carries a current of 2.0 A distributed uniformly over a cross section perpendicular to the axis of the wire. What is the magnitude of the magnetic field at a distance of 1.0 mm from the axis of the wire?
a. 0.40 mT
b. 0.80 mT
c. 0.10 mT
d. 0.20 mT
e. 0.75 mT