Question

Write Lenz's law.

Hint:

Think of Lenz's law as "electromagnetic inertia." The system (the conducting loop) resists any change to the magnetic flux passing through it, just as a massive object resists changes to its state of motion.

Answer 1

Step 1: Understanding the Concept:
Lenz's law is a fundamental principle in electromagnetic induction, which provides the direction of the induced current. It is a consequence of the law of conservation of energy.

Step 2: Detailed Explanation:
The law can be broken down into key ideas: \begin{itemize} \item Cause: A change in magnetic flux (\(\Delta\Phi_B\)) through a conducting loop.
\item Effect: An induced current is generated in the loop.
\item Opposition: This induced current creates its own magnetic field. The direction of this induced magnetic field is such that it opposes the original change in flux.
\end{itemize} For example: \begin{itemize} \item If the magnetic flux through a loop is increasing, the induced current will create a magnetic field in the opposite direction to counteract the increase.
\item If the magnetic flux through a loop is decreasing, the induced current will create a magnetic field in the same direction to try and maintain the flux.
\end{itemize} Mathematically, Lenz's law is represented by the negative sign in Faraday's law of induction: \[ \mathcal{E} = - \frac{d\Phi_B}{dt} \] where \(\mathcal{E}\) is the induced EMF. The negative sign signifies the opposition.

Step 3: Final Answer:
Lenz's law states that the direction of the induced current is such that it will oppose the change in magnetic flux that is causing it.