Question 1

What creates a magnetic field?

Accepted Answer

Moving electric charges create magnetic fields. In a wire, the flowing current (moving electrons) generates a circular magnetic field around the wire. The direction follows the right-hand rule: if your thumb points along the current, your fingers curl in the direction of the magnetic field lines.

Question 2

What is the difference between Tesla and Gauss?

Accepted Answer

Both are units of magnetic field strength. Tesla (T) is the SI unit and Gauss (G) is the CGS unit. 1 Tesla = 10,000 Gauss. Earth's magnetic field is about 25–65 μT (0.25–0.65 G). An MRI machine uses 1.5–3 T. A neodymium magnet produces about 1.2–1.4 T at its surface.

Question 3

What is the Lorentz force?

Accepted Answer

The Lorentz force F = qv × B is the force on a charged particle moving through a magnetic field. The force is always perpendicular to both the velocity and the magnetic field, which causes the particle to move in a circular path. This principle is used in particle accelerators, mass spectrometers, and CRT displays.

Question 4

How does distance affect the magnetic field from a wire?

Accepted Answer

The magnetic field from a long straight wire decreases as 1/r (inversely with distance), not 1/r² like electric and gravitational fields. This means doubling the distance halves the field strength. This slower falloff is because the wire is an extended source, not a point source.

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