We have seen that when a conducting loop moves through a magnetic fie ld, current is induced as the
result of changing magnetic flux. lf a solid conductor were used instead of a loop, as shown in Figure,
currents can also be induced along any closed loop in the conductor. The induced current are called an
eddy current.
The induced eddy currents also generate a magnetic force that opposes the motion, making it more
difficult to move the conductor across the magnetic field (Figure 1).

Since the conductor has non-vanishing resistance R, Joule heating causes a loss of power by an amount
`P = epsilon^2 /R`. Therefore, by increasing the value of R, power loss can be reduced. One way to increase R
is to laminate the conducting slab, or construct the slab by using gluing together thin strips that are
insulated from one another (see Figure-a). Another way is to make cuts in the slab, thereby disrupting the
conducting path (Figure-b).

There are important applications of eddy currents. For example, the currents can be used to suppress
unwanted mechanical oscillations. Another application is the magnetic braking systems in high-speed
transit cars.