Magnetic Force
Also known as: Lorentz force, force on a current
The force exerted on a moving charge or current-carrying conductor by a magnetic field. The magnetic force on currents is the operating principle of every electric motor.
💡 Intuition
A moving charge in a magnetic field feels a sideways push — perpendicular to both its motion and the field. It's like a cross-wind deflecting a moving ball.
Core Idea
Magnetic force acts perpendicular to velocity — it changes direction but not speed.
Formal View
🔬 Example
🎯 Why It Matters
The magnetic force on currents is the operating principle of every electric motor.
⚠️ Common Confusion
The force is zero when the charge moves parallel to the field — it's maximum when perpendicular.
💭 Hint When Stuck
When solving a magnetic force problem, first identify whether it is a moving charge (F = qvB\sin\theta) or a current-carrying wire (F = BIL\sin\theta). Then find the angle \theta between the velocity (or current direction) and the magnetic field. Finally, use the right-hand rule to determine the direction of the force.
Related Concepts
Prerequisites
Next Steps
How Magnetic Force Connects to Other Ideas
To understand magnetic force, you should first be comfortable with magnetic field, electric current and force. Once you have a solid grasp of magnetic force, you can move on to motor and electromagnetic induction.
Go Deeper
Frequently Asked Questions
What is Magnetic Force in Physics?
The force exerted on a moving charge or current-carrying conductor by a magnetic field.
Why is Magnetic Force important?
The magnetic force on currents is the operating principle of every electric motor.
What do students usually get wrong about Magnetic Force?
The force is zero when the charge moves parallel to the field — it's maximum when perpendicular.
What should I learn before Magnetic Force?
Before studying Magnetic Force, you should understand: magnetic field, electric current, force.