College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 51

A copper wire is 8.00 m long and has a cross-sectional area of 1.00 × 10 4 m 2. The wire forms a one-turn loop in the shape of a square and is then connected to a battery that applies a potential difference of 0.100 V. If the loop is placed in a uniform magnetic field of magnitude 0.400 T, what is the maximum torque that can act on it The resistivity of copper is 1.70 × 10 8 · m.