Question

which of the following changes would induce an electromotive force (emf) in the loop? when you consider each option, assume that no other changes occur

Answer 1

An electromotive force (emf) is induced in a loop when there is a change in the magnetic flux through the loop, by Faraday's and Lenz's laws.

Step-by-step explanation:

An electromotive force (emf) is induced in a loop when there is a change in magnetic flux through the area enclosed by the loop. According to Faraday's law, the emf depends on the rate of change of the magnetic field. The magnitude of this induced emf is proportional to the rate of change of the magnetic flux and the direction of the induced emf always opposes the change in magnetic flux that causes the emf, which is a statement of Lenz's law.

For example, if the current in a wire loop changes, it will alter the magnetic field and, therefore, the magnetic flux through a neighbouring loop, inducing an emf. Another case would be moving a loop relative to a magnetic field, which changes the amount of magnetic field passing through the loop's area. Additionally, changing the orientation of the loop within a magnetic field can also induce an EMF due to a change in the component of the magnetic field that is perpendicular to the loop.

Answer 2

To induce an emf in a loop, a change in magnetic flux is necessary, which can be achieved by altering the magnetic field strength, loop area, or its orientation, in accordance to Faraday's and Lenz's Laws.

Step-by-step explanation:

The question pertains to the induction of electromotive force (emf) in a loop, which is a physics concept involving Faraday's Law and Lenz's Law. A change in the magnetic flux through the loop is necessary to induce an emf. This could be accomplished by changing the magnetic field strength (B), altering the area of the loop, modifying the orientation of the loop relative to the magnetic field, or any combination thereof. These changes could arise from physical movement of the loop or the magnet, switching the current on or off in an electromagnet, or changing the current strength in a loop nearby. As indicated by Lenz's Law, the direction of the induced emf will always oppose the change in magnetic flux that caused it.

For example, if the current in a nearby loop increases, it induces a growing magnetic field, hence changing the magnetic flux through the original loop, which in turn induces an emf. Another example is rotating a coil in a fixed magnetic field, which changes the angle between the coil and the magnetic field lines, thus changing the flux. Such a concept is used in electric generators.