Chapter 29

A circular loop of wire lies flat on a level table top. A bar magnet is held stationary above the circular loop with its north pole point downward. As viewed from above, in what direction does the induced current flow in the loop of wire? a) No current is induced in the loop of wire. b) An induced current flows clockwise in the loop of wire. c) An induced current flows counterclockwise in the loop of wire. d) The direction of the induced current cannot be determined from the given information.

A circular loop of wire lies flat on a level table top in a region where the magnetic field vector points straight upward. The magnetic field suddenly vanishes. As viewed from above, in what direction does the induced current flow in the loop of wire? a) An induced current flows clockwise in the loop of wire. b) No current is induced in the loop of wire. c) An induced current flows counterclockwise in the loop of wire. d) The direction of the induced current cannot be determined from the given information

In the figure, a conducting rod is shown moving in a uniform magnetic field . Which of the following statements are true? Check all that apply. a) An electric field is established in the rod directed from point a to point b. b) The free charges in the rod are acted upon by a magnetic force. c) The magnitude of the potential difference in the rod is proportional to the strength of the magnetic field. d) The magnitude of the potential difference in the rod is inversely proportional to the length L of the rod. e) The magnitude of the potential difference in the rod is proportional to the velocity v of the rod.

Which of the following statements are true regarding electric generators? Check all that apply. a) An electric generator is used to increase or decrease an alternating current voltage. b) An electric generator converts electrical energy into magnetic energy. c) An electric generator creates a time-dependent induced voltage. d) An electric generator creates a time-independent induced voltage. e) An electric generator converts mechanical energy into electrical energy.

Which of the following statements are true concerning electromagnetic induction? Check all that apply. a) It is possible to induce a current in a closed loop of wire located in a uniform magnetic field by either increasing or decreasing the area enclosed by the loop. b) It is possible to induce a current in a closed loop of wire without the aid of a power supply or battery. c) It is possible to induce a current in a closed loop of wire remaining at rest and located in a uniform magnetic field. d) It is possible to induce a current in a closed loop of wire by change the orientation of a magnetic field enclosed by the wire. e) It is possible to induce a current in a closed loop of wire by changing the strength of a magnetic field enclosed by the wire.

In the figure, a conducting rod is shown moving to the right along U-shaped conducting rails. The apparatus is in a uniform magnetic field perpendicular to the plane of the figure. As viewed from above, in what direction does the induced current flow in the U-shaped apparatus? a) An induced current does not flow in the U-shaped apparatus. b) An induced current flows counterclockwise in the U-shaped apparatus. c) The direction of the induced current cannot be determined from the given information. d) An induced current flows clockwise in the U-shaped apparatus.

A conducting rod is being dragged along conducting rails, as shown in (Figure 1) . The magnetic field is directed out of the screen. In what direction does the induced current flow through the light bulb? a) There is no induced current. b) The induced current flows through the bulb from the left to the right. c) The induced current flows through the bulb from the right to the left.

A circular loop of conducting wire is moving through a uniform magnetic field, as shown in (Figure 2) . Is a non-zero emf induced in the loop? Yes No

Two loops of wire, each having a different radius, encircle an infinitely long solenoid, as shown in (Figure 3) . The magnetic field B⃗ is zero outside the solenoid. The current through the solenoid is increasing with time, causing the magnetic field inside the solenoid to increase with time. Which statement is true? a) The emf around the two wire loops is the same and is non-zero. b) The emf around wire loops 1 and 2 is zero since there is no magnetic field outside the solenoid. c) The emf around wire loop 2 is greater than that of loop 1.