1Who discovered the magnetic effect of electric current? What did he observe and what did he conclude?
2What is the magnetic effect of electric current? What does the direction of the field depend on?
3How can plotting compasses be used to show that the magnetic field around a straight current-carrying wire is circular?
4Why is the cardboard tapped gently in the iron filings experiment, and what pattern do the filings form?
5State Maxwell's right-hand thumb rule.
6A vertical wire carries current upwards. What is the direction of the magnetic field seen from above? What happens if the current is reversed?
7When a straight wire is connected directly to a cell for this experiment, why must the switch be turned off quickly?
8What does each of iron filings and plotting compasses show about the magnetic field around the wire?
9Compass needles around a vertical wire point clockwise when seen from above. Which way is the current flowing? Give a reason.