A wire carries a current of 0.66 A. This wire makes an angle of 58A????1 with respect to a magnetic field of magnitude 5.80  10^-5 T. The wire experiences a magnetic force of magnitude 7.30  10^-5 N. What is the length of the wire?

An ?-particle has a charge of +2e and a mass of 6.64  10^-27 kg. It is accelerated from rest through a potential difference that has a value of 1.20  10⁶ V and then enters a uniform magnetic field whose magnitude is 4.20 T. The ?-particle moves perpendicular to the magnetic field at all times.

(a) What is the speed of the ?-particle?
(b) What is the magnitude of the magnetic force on it?
(c) What is the radius of its circular path?

Two circular coils of current-carrying wire have the same magnetic moment. The first coil has a radius of 0.096 m, has 131 turns, and carries a current of 4.7 A. The second coil has 160 turns and carries a current of 8.6 A. What is the radius of the second coil?