When a magnetic field changes, what is the resulting electric field orientation relative to the magnetic field?

When a magnetic field changes, what is the resulting electric field orientation relative to the magnetic field?

• A. It is parallel to the magnetic field
• B. It is perpendicular to the magnetic field
• C. It becomes equal in magnitude to the magnetic field
• D. It disappears

Answer: (B)

Changing magnetic fields induce electric fields that form closed loops around the direction of the magnetic field. The mathematical relation curl E = - ∂B/∂t shows that the induced electric field circles around the axis of the changing B, so its lines lie in planes perpendicular to B. That makes the induced electric field perpendicular to the magnetic field. It doesn’t disappear or become equal in magnitude to B, and it isn’t parallel to B—the orientation is determined by the looping pattern around the changing field.

Changing magnetic fields induce electric fields that form closed loops around the direction of the magnetic field. The mathematical relation curl E = - ∂B/∂t shows that the induced electric field circles around the axis of the changing B, so its lines lie in planes perpendicular to B. That makes the induced electric field perpendicular to the magnetic field. It doesn’t disappear or become equal in magnitude to B, and it isn’t parallel to B—the orientation is determined by the looping pattern around the changing field.