11 Figure 30-31 shows three situations in which a wire loop lies partially in a magnetic field. The magnitude of the field is either in- creasing or decreasing, as indicated. In each situation, a battery is part of the loop. In which situations are the induced emf and the battery emf in the same direction along the loop? B= 0 B= 0 B= 0 OBincreasing OB decreasing ©Bdecreasing (a) (b) (c)

A coil lies on a horizontal plane and the south pole of the magnet is thrust into the coil with a quick movement in the direction shown in the diagram below. coil Find the direction of the induced current in the coil, when looking down on the coil from above, by answering the following questions. (a) What is the direction of the magnetic field due to the magnet in the center of the coil? O +x O -x O +y O -y O +z O -7 (b) As the magnet is moved in the direction indicated, how will the magnetic flux in the coil change? O increase O decrease O remain the same

Induced EMF Below is a closed conducting loop within a magnetic field (for direction see picture). The loop is a circle with a radius of r = 5.00 cm. The magnetic field is decreasing in the direction shown at a rate of dB/dt = 157.0 mT/s. The circle wire has 305.0 loops around it. The wire has a total resistance of R = 2.80 Ohms. Magnetic Field (into the page) 8) What is the induced current around the wire in this system? (use a negative value for a clockwise current) Make sure to give your answer in an appropriate number of significant figures as well as including units with your answer. Your Answer: Answer units PLEASE TAKE OUT TRASH AT EOS IG

A wire loop is spinning on its axis in a uniform magnetic field. Is there an emf induced in the loop? Yes, as long as the angular velocity is nonzero Yes, but only if the angular velocity of the loop is increasing or decreasing Yes, but only if the angular velocity of the loop is constant O No