Quiz 9

• A loop of wire lies flat on the horizontal surface in an area with uniform magnetic fielddirected vertically up. The loop of wire suddenly contracts to half of its initial diameter.As viewed from above induced electric current in the loop is:

  counterclockwise
• A loop of wire lies flat on a horizontal surface. A bar magnet is held above the center of aloop with south pole pointing down. Magnet is released. As magnet approaches the loopof wire, the induced current in this wire is:

  clockwise
• Two conducting loops of the same diameter, #1 made of copper and #2 made ofaluminum wires of the same length and cross-sections are placed on the horizontalsurface in uniform magnetic field directed vertically up. Magnetic field vanishessuddenly. While magnetic field is decreasing, direction of induced emf force as viewedfrom above in these loops is:

  counterclockwise
• Two conducting loops of the same diameter, #1 made of copper and #2 made ofaluminum wires of the same length and cross-sections are placed on the horizontalsurface in uniform magnetic field directed vertically up. Magnetic field vanishessuddenly. The magnitude of induced emf in wire #1 is

  Same as in the wire #2
• A long straight horizontal wire carries constant in time current due east. A conductinghorizontally oriented conducting loop is approaching this wire from south. The inducedcurrent in this loop is:

  counterclockwise