Flux Counts What Goes Through

You'll learnto read flux off a surface's normal rather than off its area, and to keep "the net flux is zero" and "the field is zero" apart.

Twenty field lines cross the screen, and a flat sheet is held in them. How much of the field goes through it? Count the lines — then tilt the sheet, curve it, close it, and put a charge inside. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · COUNT THE LINES · THE NORMAL DECIDES · CLOSED SURFACES · v2

count the lines through the surface · zero net flux is not zero field

Before you start

What you're looking at

Twenty field lines, and a flat sheet seen edge-on as a white bar. The short amber arrow is the sheet's normal.

The question

How much of the field goes through the sheet, and what changes that?

Step 1 / 12