AQA P2 and P3 Question Game

You answer the previous question and then add another question.
I'll begin: What causes short-sightedness and long-sightedness, and which lens are used to correct them?

Short-sightedness - too powerful eye-lens or a long eyeball. A diverging lens / concave lens will correct this.
Long-sightedness - eye-lens is too weak. A converging lens / convex lens will correct this.

How does a transformer work?

Explain the motor effect and the uses of brush and split ring commutators?

The motor effect occurs when a magnetic field is inside of another magnetic field, and they interact; they push on each other, and create a force.
Split-ring commutators are used in electric motors, and they make it so that the electric motor can continue to turn. This is because when it gets to the next ring of the split-ring commutator, the current reverses, causing the force to push the parts of the electric motor in the opposite way to which they were being pushed before.

What are the conditions in which total internal reflection can take place? Give an example of what total internal reflection can be used for.