This induced emf can produce a current, which will then create its own magnetic
field. The direction of the induced current is determined by the polarity of the
induced emf and is given by Lenz’s law (which also explains the minus sign in the
equation above): The induced current will always flow in the direction that
opposes the change in magnetic flux that produced it. If this were not so, then the
magnetic flux created by the induced current would magnify the change that
produced it, and energy would not be conserved. Note that it is common practice to
refer to the “direction” of flux. Keep in mind that flux is scalar, and so has no
direction. Talking about flux having a direction makes applying Lenz’s law easier,
but what we are really referring to is the direction of the field producing the flux.
Questions 4-5The circular loop of Example 14.1 rotates at a constant angular
speed through 60° in 0.5 s.