The figure shows three circuits consisting of straight radial parts and concentric circular arcs (half circles of radii r and 3r). The circuits carry the same current. Rank them according to the magnitude of magnetic field (B1, B2, and B3) produced at the center of curvature (the dot), greatest first i i B2 B1 B3

The loop shown below has a radius of 12 cm and is placed in a magnetic field oriented into the page, as shown. The resistance of the loop is 5 ohms. The magnitude of the magnetic field may be modeled as B(t )=3−2t . Determine the magnitude and direction of the current in the loop at time t = 3 seconds.

The figure shows three infinitely long wires that carry currents directly into or out of the plane of the figure, as indicated. What is the magnitude (T) of the net magnetic field at the origin? i₁=5.00 A, i2=2.00 A, i3-7.00 A, and d = 2.00 m. d d X

Helmholtz coils are frequently used in experiments because they create a uniform magnetic field about their central axis. For example, they are traditionally used in the experiment for the measurement of the charge-to-mass ratio of the electron. Helmholtz coils are two coils separated by a distance equal to their radius that carry equal currents in the same direction." Suppose the radius of the coils is R 18.00 cm and each coil carries a current of /== 11.50 A and has N 340.0 turns. The coils are in the yz plane where one coil's center is at x = 0 the other coil's center is at x = R. -X=R 00