Honors Physics

# Questions - Week 37

1. What causes magnetic force?
2. What causes magnetic field?
3. What causes permanent magnetism?
4. If current is moving north through a wire, and the magnetic field surrounding the wire is toward the east, which way will the wire move? Is this a motor or a generator?
5. A wire moves north due to a current passing through it to the west. Is this a motor or a generator? Which direction is the magnetic field?
6. Take a loop of wire with a radius of 2.0 cm. A B field is perpendicular to the area enclosed by the wire. If the field is reduced to zero from 0.55 T in 0.25 s, what is the induced emf between the ends of the wire?
7. What is the direction of the induced current in the wire loop? The arrow shows the direction of the moving magnet.

8. A magnetic field is perpendicular to a rectangular coil of wire (0.040 m by 0.060 m) consisting of exactly 100 loops. In order to induce a voltage of 1.5 V in the coil in 0.050 s, how much would the B field need to change?