Quiz #9

When two 1-ohm resistors are connected in series, their combined resistance is a) 2 ohms, and when in parallel, 1/2 ohm. b) 1 ohm, and when connected in parallel, 2 ohms. c) 1/2 ohm, and when in parallel, 2 ohms. d) 2 ohms, and when in parallel, 1 ohm. e) none of these

a) 2 ohms, and when in parallel, 1/2 ohm.

The electric power of a lamp that carries 2 A at 120 V is a) 240 watts. b) 1/6 watts. c) 20 watts. d) 60 watts. e) 2 watts.

a) 240 watts.

Stretch a copper wire so that it is thinner and the resistance between its ends a) increases. b) decreases. c) remains unchanged.

a) increases.

A wire carrying a current is normally charged a) not at all. b) negatively. c) positively.

a) not at all.

Electrons are made to flow in a wire when there is a) an imbalance of charges in the wire. b) a potential difference across its ends. c) more potential energy at one end of the wire than the other.

b) a potential difference across its ends.

As more lamps are put into a series circuit, the overall current in the power source a) increases. b) decreases. c) stays the same.

b) decreases.

Three resistors, 1-ohm, 2-ohm, and 3- ohm are connected in parallel. If they were connected in series instead their equivalent resistance would be a) 7 times as great. b) 13 times as great. c) 11 times as great. d) 9 times as great. e) None of the above choices are correct.

c) 11 times as great.

A 4-ohm resistor is connected in parallel with a 6-ohm resistor. This combination produces an equivalent resistance of a) 5.5 ohms. b) 5 ohms. c) 2.4 ohms. d) 4 ohms. e) 10 ohms.

c) 2.4 ohms.

A 60-W light bulb and a 100-W light bulb are connected in series to a 120 V outlet. Which light bulb has more current in it? a) the 100-W bulb b) the 60-W bulb c) Both have the same current.

c) Both have the same current.

An electrical diode is useful for a) storing electrical energy. b) boosting voltage. c) changing ac to dc. d) limiting current. e) voltage modification.

c) changing ac to dc.

Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is a) greatest across the lamp with the thick filament. b) greatest across the lamp with the thin filament. c) the same in both lamps.

c) the same in both lamps.

A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is a) $0.55. b) $5.50. c) $0.22. d) $2.20. e) none of these

d) $2.20.

When a 10-V battery is connected to a resistor, the current in the resistor is 2 A. What is the resistor's value? a) 2 ohms b) more than 20 ohms c) 20 ohms d) 5 ohms e) 10 ohms

d) 5 ohms

A capacitor is useful in a) switching dc to ac in a circuit. b) increasing or decreasing voltage. c) increasing the current in a resistor. d) smoothing pulsed current. e) boosting the energy output of a circuit.

d) smoothing pulsed current.

What is the resistance of a 120-W incandescent lamp connected to a 120-V power supply? a) 1 ohm b) 144 ohms c) 100 ohms d) 60 ohms e) none of these

e) none of these