1 Answer
Lenz's Law is a principle in electromagnetism that helps us understand how induced currents behave in a conductor when it experiences a change in magnetic flux. It is a crucial concept in the study of electromagnetic induction, especially in Class 12 Physics.
Statement of Lenz's Law:
Lenz’s Law states that the direction of the induced current (or electromotive force, EMF) is such that it opposes the change in magnetic flux that produced it.
This means that if the magnetic flux through a coil or conductor increases, the induced current will flow in a direction that creates a magnetic field opposing the increase in flux. Similarly, if the magnetic flux decreases, the induced current will flow in such a way as to oppose the decrease in flux.
Key Points:
Example:
Formula:
The magnitude of the induced EMF (electromotive force) is given by Faraday’s Law:
\[
|\mathcal{E}| = -\frac{d\Phi_B}{dt}
\]
Where:
The negative sign indicates that the induced EMF opposes the change in magnetic flux, as described by Lenz’s Law.
In short, Lenz’s Law helps us predict the direction of induced currents and ensures that energy is conserved in electromagnetic induction processes.
Statement of Lenz's Law:
Lenz’s Law states that the direction of the induced current (or electromotive force, EMF) is such that it opposes the change in magnetic flux that produced it.This means that if the magnetic flux through a coil or conductor increases, the induced current will flow in a direction that creates a magnetic field opposing the increase in flux. Similarly, if the magnetic flux decreases, the induced current will flow in such a way as to oppose the decrease in flux.
Key Points:
- Opposition to change: The key idea is that the induced current works against the change in the magnetic field. This is a consequence of the conservation of energy.
- Conservation of Energy: The law ensures that energy is not created or destroyed. If the current were to flow in the same direction as the change in flux, it would violate the principle of conservation of energy.
- Faraday’s Law: Lenz's Law is actually a part of Faraday's Law of electromagnetic induction. Faraday’s Law gives the magnitude of the induced EMF, and Lenz’s Law gives its direction.
Example:
- If you push a magnet toward a coil, the magnetic flux through the coil increases. The induced current will flow in such a way that it creates a magnetic field opposing the motion of the magnet.
- If you pull the magnet away from the coil, the magnetic flux decreases. The induced current will flow in a direction that creates a magnetic field trying to keep the magnet from moving away.
Formula:
The magnitude of the induced EMF (electromotive force) is given by Faraday’s Law:\[
|\mathcal{E}| = -\frac{d\Phi_B}{dt}
\]
Where:
- \(\mathcal{E}\) is the induced EMF,
- \(\Phi_B\) is the magnetic flux,
- \(t\) is time.
The negative sign indicates that the induced EMF opposes the change in magnetic flux, as described by Lenz’s Law.
In short, Lenz’s Law helps us predict the direction of induced currents and ensures that energy is conserved in electromagnetic induction processes.