## Tuesday, November 4, 2014

### Magnetic Field and Magnetic Forces: Problems

#### Chapter 20, problem 31.

A rectangular x1 cm by x2 cm circuit carrying an x3 A current is oriented with its plane parallel to a uniform x4 T magnetic field (Figure 20.62, page 693).
(a) Find the magnitude and direction of the magnetic force on each straight segment of this rectangular circuit.
(b) Find the magnitude of the net force on the entire circuit.
(c)  Find the magnitude of the net torque on the entire circuit.

#### Chapter 20, problem 57.

A circular metal loop is x1 cm in diameter.
How large a current must flow through this metal so that the magnetic field at its center is equal to the magnetic field of x2 T?

#### Chapter 20, problem 62.

Two circular concentric loops of wire lie on a tabletop, one inside the other.
The inner loop has a diameter of x1 cm and carries a clockwise current of x2 A,
as viewed from above, and the outer wire has a diameter of x3 cm.
What must be the magnitude and direction (as viewed from above) of the current in the outer loop so that the net magnetic field due to this combination of loops is zero at the common center of the loops?

#### Chapter 20, problem 64.

A solenoid contain N coils of very thin wire evenly wrapped over a length of x1 cm.
Each coil is x2 cm in diameter.
If yhis solenoid carries a current of x3 A, what is the magnetic field at its center?