The Slope Is the Signal

You'll learnwhich angle goes into the flux, why the biggest flux can come with zero emf, how a field that never changes can still light a bulb, and which way the induced current runs.

A loop of wire with a small bulb in it, sitting in a magnetic field. While the field is changing the bulb glows; the moment the field holds steady, at its strongest, the bulb goes dark. Everything in this topic lives in that one observation. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · CHANGE LIGHTS THE BULB · SLOPE, NOT HEIGHT · OPPOSE THE CHANGE · v2

change lights the bulb · the emf is the slope · oppose the change

Before you start

What you're looking at

A loop of wire with a small bulb in it, sitting in a magnetic field drawn as crosses.

The question

What has to happen to the field before the bulb lights up?

Step 1 / 12