Under what conditions will there be an induced electric current through an ammeter connected to a fixed coil of wire next to a moving bar magnet?

Under what conditions will there be an induced electric current through an ammeter connected to a fixed coil of wire next to a moving bar magnet?

• A. Only when moving steadily toward the coil
• B. When moving toward or away from the coil with varying speed
• C. Only if moving away from the coil
• D. There is no condition for induced current

Answer: (B)

Induced electric current can be generated in a coil of wire due to the changing magnetic fields in its vicinity, as described by Faraday's law of electromagnetic induction. When a bar magnet moves relative to a fixed coil, it creates a change in the magnetic flux through the coil. The key point is that this change in magnetic flux is what induces the current. When the magnet is moving toward the coil, the magnetic flux through the coil increases, causing an induced current. Conversely, when the magnet moves away from the coil, the magnetic flux decreases, which also results in an induced current. If the magnet is moving at a varying speed, it can further alter the rate of change of magnetic flux, thereby enhancing the induced current as the flux is changing more rapidly or slowly. This principle underlines that induced current can occur under both conditions of moving toward and moving away from the coil, especially if there is a changing speed associated with the magnet’s movement, leading to varying rates of flux change. Thus, when considering the nature of electromagnetic induction, it's clear that this variability and directional change are essential for inducing current in the coil.

Induced electric current can be generated in a coil of wire due to the changing magnetic fields in its vicinity, as described by Faraday's law of electromagnetic induction. When a bar magnet moves relative to a fixed coil, it creates a change in the magnetic flux through the coil.

The key point is that this change in magnetic flux is what induces the current. When the magnet is moving toward the coil, the magnetic flux through the coil increases, causing an induced current. Conversely, when the magnet moves away from the coil, the magnetic flux decreases, which also results in an induced current. If the magnet is moving at a varying speed, it can further alter the rate of change of magnetic flux, thereby enhancing the induced current as the flux is changing more rapidly or slowly.

This principle underlines that induced current can occur under both conditions of moving toward and moving away from the coil, especially if there is a changing speed associated with the magnet’s movement, leading to varying rates of flux change. Thus, when considering the nature of electromagnetic induction, it's clear that this variability and directional change are essential for inducing current in the coil.