Question

when a magnet is plunged into a coil at speed v, as shown in (figure 1), a voltage is induced in the coil and a current flows in the circuit.

Answer 1

The question deals with Faraday's Law of electromagnetic induction, wherein a voltage and current are induced in a coil when a magnet's motion changes the magnetic flux through the coil. This is fundamental to understanding electromagnetic phenomena and is applied in various technologies like generators and transformers.

Step-by-step explanation:

The student's question pertains to the induction of an electromotive force (emf) and current in a coil when a magnet is moved through it. This is described by Faraday's Law of electromagnetic induction, which states that a voltage is induced in a coil when there is a change in magnetic flux through the coil. The faster the magnet is moved through the coil (speed v), the greater the induced voltage and the resultant current. The direction of the current depends on the direction of the magnet's movement and its polarity. Lenz's Law further explains that the induced current will create a magnetic field that opposes the change in flux caused by the magnet.

Induction-based experiments, such as Faraday's, demonstrate that changing magnetic fields can create currents. The movement of a magnet (increasing or decreasing the magnetic field within a coil), the rate of change (speed of movement), and the direction (related to the polarity of the magnet and the direction of movement) all influence the induced emf according to the relationship ε = Blv, where B is the magnetic field strength, l is the length of the conductor, and v is the velocity at which the conductor moves perpendicular to the magnetic field.

Answer 2

The question asks about Faraday's Law of electromagnetic induction, where moving a magnet through a coil induces a voltage that generates a current, the direction and magnitude of which depend on the speed and orientation of the magnet's movement relative to the coil.

Step-by-step explanation:

The student's question relates to the phenomenon where a voltage is induced in a coil when a magnet is moved through it, and this is described by Faraday's Law of electromagnetic induction. This law explains that a current is induced in a coil only when there is a relative motion between the magnet and the coil, resulting in a change in magnetic flux through the coil. According to Faraday's experiment, the direction of the induced current depends on the direction of the magnet's motion and the polarity of the magnet. Also, the magnitude of the induced voltage or electromotive force (emf) increases with the speed of the magnet's motion, described by the equation ε = Blv, where B is the magnetic field, l is the length of the conductor within the field, and v is the velocity of the motion.

Furthermore, Lenz's law explains that the direction of the induced current will be such that it creates a magnetic field opposing the change that produced it. This is a manifestation of the conservation of energy, ensuring that the induced emf acts to oppose the change in flux. This principle is illustrated in the Faraday's experiments and the behavior of currents induced by changing magnetic fields.