What Is the Magnetic Force on a Moving Charge?

TL;DR

The magnetic force on a moving charge is determined by the equation F = q(v × B), where F is the magnetic force, q is the charge's magnitude, v is its velocity, and B is the magnetic field. The direction of this force is perpendicular to both the velocity of the charge and the magnetic field. The unit of the magnetic field is the tesla, defined as a newton per ampere-meter.

Transcript

We know a little bit about magnets now. Let's see if we can study it further and learn a little bit about magnetic field and actually the effects that they have on moving charges. And that's actually really how we define magnetic field. So first of all, with any field it's good to have a way to visualize it. With the electrostatic fields we drew fi... Read More

Key Insights

• 💈 Magnetic field lines represent the path a magnetic north monopole would take, always from the north pole to the south pole of a magnet.
• 💈 Compass needles align tangentially to magnetic field lines, with the north pole seeking the south pole of the magnet.
• 🈂️ Magnetic fields are defined in relation to their effects on moving charges, with the force on a charge equal to the charge's magnitude multiplied by the cross product of its velocity and the magnetic field.
• 🍉 The magnitude of a magnetic field is determined in terms of the effect it has on a moving charge, and its units are measured in teslas.

Questions & Answers

Q: How are magnetic field lines drawn and what do they represent?

Magnetic field lines are drawn from the north pole to the south pole of a magnet, representing the path a magnetic north monopole would take.

Q: What is the direction of a compass needle and how does it relate to magnetic fields?

The direction of a compass needle is tangential to the field lines, with the north pole seeking the south pole of the magnet.

Q: How is the magnitude of a magnetic field determined?

The magnitude of a magnetic field is determined by the effect it has on a moving charge, with the force on the charge equal to the charge's magnitude multiplied by the cross product of its velocity and the magnetic field.

Q: What are the units of the magnetic field and what is it named after?

The units of the magnetic field are newton seconds per coulomb meter, which is named after Nikolai Tesla. One tesla is equal to one newton second per coulomb meter.

Summary & Key Takeaways

• Magnetic field lines are drawn from the north pole to the south pole of a magnet, representing the path a magnetic north monopole would take.

• The direction of a compass needle is tangential to the field lines, with the north pole pointing towards the south pole of the magnet.

• Magnetic fields are defined in terms of their effects on moving charges, with the force on a charge equal to the magnitude of the charge multiplied by the cross product of its velocity and the magnetic field.