1. Indicate which of the following will produce a magnetic field:
(a) A magnet.
(b) The Earth.
(c) An electric charge at rest.
(d) A moving electric charge.
(e) An electric current.
(f) The voltage of a battery not connected to anything.
(g) An ordinary piece of iron.
(h) A piece of any metal.
2. A current in a wire points into the page as shown at the right. In which direction is the magnetic field at point A (choose below)?
(a) →
(b) ←
(c) ↓
(d) ↑
(e) None of these.