CHAPTER 13 SELF-QUIz K/U Knowledge/Understanding T/I Thinking/Investigation C Communication A Application

For each question, select the best answer from the four alternatives. 1. In Faraday’s ring, which of the following actions

causes electromagnetic induction in the secondary coil? (13.1) K/U

(a) turning the direct current on in the primary circuit(b) turning the direct current off in the primary circuit(c) turning the direct current on and off repeatedly

in the primary circuit(d) all of the above

2. Which of the following descriptions is consistent with Lenz’s law? (13.2) K/U

(a) If a north magnetic pole is moved into a coil, the same side of the coil is now a south magnetic pole.

(b) If a north magnetic pole is moved out of a coil, the same side of the coil is now a south magnetic pole.

(c) If a south magnetic pole is moved into a coil, the opposite side of the coil is now a south magnetic pole.

(d) If a south magnetic pole is moved out of a coil, the opposite side of the coil is now a north magnetic pole.

3. Alternating current has which of the following properties? (13.3) K/U

(a) Electrons travel in one direction only.(b) Voltage and current rise and fall periodically.(c) Electrons travel from the distribution panel to

your room to operate your lamp.(d) Voltage and current remain constant.

4. Which of the following statements is true about an AC generator? (13.4) K/U

(a) It contains a split ring commutator and brushes.(b) Its spin rate is independent of the frequency of

electricity generated.(c) It contains two different slip rings and brushes.(d) It produces maximum current when the coils of wire

are perpendicular to the external magnetic field. 5. Which of the following correctly describes a step-up

transformer? (13.5) K/U

(a) The number of windings on the primary coil is greater than the number of windings on the secondary coil.

(b) The current in the primary coil is less than the current in the secondary coil.

(c) The voltage on the primary coil is less than the voltage on the secondary coil.

(d) The ratio of the number of primary windings to the number of secondary windings is greater than one.

6. Which of the following correctly describes a step-down transformer? (13.5) K/U

(a) The number of windings on the secondary coil is greater than the number of windings on the primary coil.

(b) The current in the secondary coil is greater than the current in the primary coil.

(c) The voltage on the secondary coil is greater than the voltage on the primary coil.

(d) The ratio of the number of primary windings to the number of secondary windings is less than one.

7. Which of the following descriptions would provide the most efficient electrical energy transmission? (13.6) K/U

(a) low-voltage and high-current DC(b) high-voltage and low-current AC(c) low-voltage and high-current AC(d) high-voltage and high-current AC

Indicate whether each statement is true or false. If you think the statement is false, rewrite it to make it true.

8. A magnetic field with a larger change in magnitude induces less current in a conductor than a magnetic field with a smaller change in magnitude. (13.1) K/U

9. The magnetic field induced in a coil always aligns exactly with the magnetic field that produced it. (13.2) K/U

10. A fuse has a metal strip in it that heats up and melts when too much current is drawn through it, and then it needs to be replaced. (13.3) K/U

11. The majority of devices used in North American homes require 240 V. (13.3) K/U

12. AC generators in North America produce electricity with a frequency of 60 Hz. (13.4) K/U

13. A step-up transformer has more windings on the secondary coil than on the primary coil. (13.5) K/U

14. In a step-up transformer both the current and the potential difference are increased in the secondary circuit. (13.5) K/U

15. The power lost in transmission is proportional to the square of the current. (13.6) K/U

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NEL Chapter 13 Self-Quiz 31

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