Mistake Master
Mistake Master · AP Physics 2 · Unit 15 · Step-Through Animation
One Photon at a Time
You'll learnwhy turning a lamp up cannot start the current, what the colour of the light decides, and how to read the stopping-voltage graph without swapping the slope for the intercept.
Point a red lamp at a metal plate and nothing comes off, however blinding it gets. Swap in a dim green lamp and the current starts at once. Twelve short steps; press Next for each one.
colour decides whether · brightness decides how many · the slope is universal
Before you start
What you're looking at
A lamp shining on a metal plate inside a phototube, with a meter reading how many electrons cross to the collector.
The question
What decides whether electrons come off, how fast they leave, and how many cross each second?
Step 1 / 12