9. Compare the magnetic field of the Earth to the magnetic field
of a bar magnet.
10. Explain the difference between the geographical North Pole
and the magnetic North pole of the Earth.
11. Draw magnetic field lines for two similar magnetic poles and
two dissimilar magnetic poles.
12. A wire 0.50 m long carrying a current of 8.0 A is at right angles
to a uniform magnetic field. The force on the wire is 0.40 N.
What is the strength of the magnetic field?
13. The current through a wire 0.80 m long is 5.0 A. The wire is per-
pendicular to a 0.60 7 magnetic field. What is the magnitude
of the force on the wire?
14. An electric wire in the wall of a building carries a current of 25
A vertically upward. What is the magnetic field at a distance
of 10 cm from the wire?
15. Determine the magnitude and direction of magnetic force on
an electron traveling 8.75 x 105 m/s horizontally to the East in
a vertically upward of magnetic field 0.75 T.
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