What does Lenz's law state about the direction of the induced current?

What does Lenz's law state about the direction of the induced current?

• A. It opposes the change in magnetic flux
• B. It enhances the change in magnetic flux
• C. It is perpendicular to the change in flux
• D. It has no relation to flux

Answer: (A)

When magnetic flux through a closed loop changes, an emf is induced in a direction that opposes that change. This opposition is built into Faraday’s law through the minus sign: emf = - dΦ/dt. So if the flux through the loop is increasing in a certain direction, the induced current creates a magnetic field in the opposite direction to oppose that increase; if the flux is decreasing, the induced current generates a field in the same direction as the original flux to help keep it from falling. You can determine the actual current direction by using the right-hand rule once you know whether the flux is rising or falling. The essential point is that the induced current always acts to oppose the change in magnetic flux.

When magnetic flux through a closed loop changes, an emf is induced in a direction that opposes that change. This opposition is built into Faraday’s law through the minus sign: emf = - dΦ/dt. So if the flux through the loop is increasing in a certain direction, the induced current creates a magnetic field in the opposite direction to oppose that increase; if the flux is decreasing, the induced current generates a field in the same direction as the original flux to help keep it from falling. You can determine the actual current direction by using the right-hand rule once you know whether the flux is rising or falling. The essential point is that the induced current always acts to oppose the change in magnetic flux.