Motional EMF

Inducing a voltage by moving a conductor through a magnetic field.

The Concept: Lorentz Force

When a conducting rod moves through a magnetic field, the free charges inside it (electrons) also move. This results in a magnetic force, called the Lorentz force ($ \vec{F} = q\vec{v} \times \vec{B} $), acting on the charges. This force pushes the charges to opposite ends of the rod, creating a separation of charge. This charge separation is an induced EMF (voltage).

How to Use the Lab

Drag the metal rod left or right to give it a velocity ($v$).
Observe the force vectors on the charges inside the rod.
Watch the charges separate and the light bulb glow.
The "What's Happening?" panel gives a real-time explanation.

Controls

B-Field Strength: 0.5 T

Rod Length (L): 150 px

Live Analysis

$\mathcal{E} = B L v$

Velocity ($v$): 0.00 m/s

EMF ($\\mathcal{E}$): 0.000 V

What's Happening?

Rod is stationary. No motion means no Lorentz force on the charges, so no voltage is induced.