Answer to Question #66512 in Electricity and Magnetism for Chelsea

Question

You had so much fun making a capacitor that you decide to make an electric motor.
You have copper wire (resistivity, ρ = 1.70 × 10−8 Ω m) with a cross-sectional area of
2.00 × 10−7 m2
, and using 1.00 m of this wire you make a rectangular coil with sides
having lengths of 1.50 cm and 1.00 cm. Your ceramic magnet has a magnetic field of
0.30 T in which you will immerse this coil. You will power it with a standard D-cell
battery, so the potential difference is 1.50 V. Determine the maximum torque on your
electric motor. (There are a lot of little steps in this problem, including geometry and
equations from prior chapters.)