Question

A magnetic field does not interact with:

• A. An electric charge at rest
• B. A moving electric charge
• C. A current-carrying straight conductor
• D. A moving permanent magnet

Hint:

Remember, the magnetic field only interacts with moving charges. For a stationary charge, the magnetic force is zero, as there is no velocity to create a cross product with the magnetic fiel(D)

Answer 1

The Correct Option is A

Magnetic fields exert a force on moving electric charges, which is known as the Lorentz force. The force on a charged particle due to a magnetic field is given by the equation: \[ \vec{F} = q (\vec{v} \times \vec{B}) \] Where: - \( \vec{F} \) is the force on the particle, - \( q \) is the charge of the particle, - \( \vec{v} \) is the velocity of the particle, - \( \vec{B} \) is the magnetic fiel(D) For a charge that is at rest, the velocity \( \vec{v} = 0 \), which means the cross product \( \vec{v} \times \vec{B} = 0 \). Therefore, there is no force acting on a stationary electric charge when it is placed in a magnetic fiel(D) However, for a moving charge, a current-carrying conductor, or a moving permanent magnet, the magnetic field exerts a force. Thus, the correct option is that a magnetic field does not interact with an electric charge at rest.