For a loop of current-carrying wire in a uniform magneticfield the potential energy is a minimum if the magnetic dipolemoment of the loop is: in the same direction as the field at an angle of 45° to the field perpendicular to the field none of these in the direction opposite to that of the field

Check Your Understanding Shown below is a rod of length l that is rotated counterclockwise around the axis through O by the torque due to mg . Assuming that the rod is in a uniform magnetic field B , what is the emf induced between the ends of the rod when its angular velocity is ? Which end of the rod is at a higher potential?

12.7 Check Your Understanding What is the ratio of the magnetic field produced from using a finite formula over the infinite approximation for an angle of (a) 85°? (b) 89°? The solenoid has 1000 mins in 50 cm with a current of 1.0 A flowing through the coils

Check Your Understanding The wire loop forms a full circle of radius R and current I. What is the magnitude of the magnetic field at the center?

Check Your Understanding Using Example 12.5, at what distance would you have to move the first coil to have zero measurable magnetic field at point P?

Is B constant in magnitude for points that lie on a magnetic field line?

Is the magnetic field of a current loop uniform?

The current in a long solenoid of radius 3 cm and 20 turns cm is varied with time at a rate of 2 A/s. Find the electric field at a distance of 4 cm from die center of the solenoid.

The magnetic field perpendicular to a single sire loop of diameter 10.0 cm decreases fron 0.50 T to zero. The re Is made of copper and has a diameter of 2.0 mm and length 1.0 cm. How much charge moves thrnugh the re while tt field is changing?

Magnetic field inside a torus. Consider a torus of rectangular cross-section with inner radius a and outer radius b. N turns of an insulated thin wire are wound evenly on the toms tightly all around the torus arid connected to a battery producing a steady current f in the wire. Assume that the current on the top and bottom surfaces in the figure is radial, and the current on the inner and outer radii surfaces is vertical. Find the magnetic field inside the toms as a function of radial distance r from the axis.