1. Lots of fun! Win valuable prizes!

2. 1. Which one of the following circuits has the largest resistance? 20 V 2 V 8 V 10 V 2 V

3. 2. When two light bulbs are connected in series, the A. same amount of current always flows through each bulb. B. current through each light bulb is proportional to the resistance of the bulb. C. neither A nor B

4. 3. Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have A. less resistance. B. the same resistance. C. more resistance.

5. 4. When one light bulb in a series circuit containing several light bulbs burns out A. nothing changes in the rest of the circuit. B. the other light bulbs burn brighter. C. none of the other bulbs will light up.

6. 5. Surrounding every moving electron is A. an electric field. B. a magnetic field. C. both A and B D. none of the above

7. 6. If you break a bar magnet in half, each half A. becomes a bar magnet with two poles. B. becomes unmagnetized. C. contains one magnetic pole.

8. 7. Magnetic field strength is A. strongest close to a magnet. B. constant everywhere around a magnet. C. strongest far from a magnet.

9. 8. Magnetic fields are produced by A. moving particles. B. moving particles of earth. C. moving charged particles. D. charges at rest. E. none of the above

10. 9. Magnetic field lines surrounding a magnet are conventionally drawn A. from north to south. B. from south to north. C. either way.

11. 10. Moving electric charges will interact with A. an electric field. B. a magnetic field. C. both A and B D. none of the above

12. 11. Loops of wire in a motor rotate because a A. magnet attracts stationary electrons in the wire. B. current exerts a force on the loop, causing it to rotate. C. magnetic field exerts forces on moving electrons in the loop. D. battery effectively pushes a loop around in the field. E. none of the above

13. 12.Which geographic pole of the earth is nearest the magnetic north pole of the earth? A. South Pole B. North Pole C. both A and B

14. 13. Electric current can best be induced in a wire by A. moving a magnet up and down near the wire. B. rotating the wire. C. stretching the wire. D. setting the wire near a magnet. E. none of the above

15. 14. A magnet is moved in and out of a coil of wire connected to a voltmeter. If the number of coils doubles, the induced voltage A. halves. B. is the same. C. doubles. D. quadruples. E. none of the above

16. 15. A magnet is moved in and out of a coil of wire connected to several lamps. If the number of turns in the coil is doubled A. it is harder to move the magnet. B. it is easier to move the magnet. C. there is no difference in moving the magnet.

17. 16. A device consisting of a coil that is mechanically rotated in a stationary magnetic field is called A. a generator. B. a motor. C. a magnetic pole. D. a dipole. E. a transformer.

18. 17. The magnetic field strength inside a current- carrying coil will be greater if the coil encloses a A. iron rod. B. vacuum. C. glass rod. D. wooden rod. E. none of the above

19. 18. A device that transforms electrical energy to mechanical energy is a A. magnet. B. generator. C. transformer. D. motor. E. none of the above

20. 19. If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with a greater speed A. the same voltage is induced. B. a smaller voltage is induced. C. a larger voltage is induced.

21. 20. A device that uses two coils around an iron core to change the voltage across a circuit is called a A. diode. B. voltmeter. C. generator. D. motor. E. transformer.

22. 21. A transformer works because A. electricity is transferred to a coil via an iron core. B. a changing magnetic field is transferred to a coil via an iron core. C. electricity is induced in a rotating coil. D. electricity flows from a primary coil to a secondary coil.

23. 22. To reduce the amount of energy lost as heat in power lines, electric energy is transmitted from power plants to consumers A. as alternating current at low voltage. B. as alternating current at high voltage. C. as direct current at low voltage. D. as direct current at high voltage.

24. 23. In the diagram below, a magnetic field is directed toward the left. A negatively charged particle moves in the direction of the dashed arrow. What is the direction of the magnetic force acting on the particle? A. to the right B. upward C. to the left D. downward E. into the page F. out of the page -

25. Bonus question time After your team learns its score, you may wager any amount of points up to your total. Submit your wagers on a slip of paper to Mr. Maley.

26. Bonus question The voltage across a transformer primary coil that has 200 turns is 120 V. What is the voltage across the secondary coil, which has 40 turns?

27. Answer: 24 V