Physic

Q: A lamp rated 23W-120V means that it will deliver 23 W A) when the voltage across it is 120 V. B) whether or not it is connected to 120 V. C) as long as the current is ac. D) none of the above

Q: What is the resistance of a 120-W incandescent lamp connected to a 120-V power supply? A) 1 ohm B) 60 ohms C) 100 ohms D) 144 ohms E) none of the above

Q: A power line with a resistance of 2 ohms draws a current of 80 A. The power dissipated in the line is A) 40 W. B) 160 W. C) 320 W. D) 12,800 W. E) none of the above

Q: For electric power that costs 10 cents per kilowatt hour, the cost of operating a 110-V heater that uses 20 A for 10 hours is A) $0.22. B) $0.55. C) $2.20. D) $5.50. E) none of the above

Q: A certain bulb with a resistance of 95 ohms and labeled "150 W" is designated for use in a A) 120-V circuit. B) 240-V circuit. C) either D) not enough information

Q: An electric heater is rated at 300 W when used in a 110-V circuit. The safety fuse in the circuit can accommodate 15 A of current. How many heaters can be safely operated in the circuit? A) 2 B) 3 C) 4 D) 5 E) more than 5

Q: Which of these lamps is the longer lasting in a common circuit? A) incandescent lamp B) compact fluorescent lamp C) light-emitting diode D) all about the same

Q: A compact fluorescent lamp gives more light output for A) less power. B) the same power. C) greater resistance.

Q: A 100-W lamp glows brighter than a 25-W lamp. The electric resistance of the 100-W lamp is A) less. B) greater. C) the same.

Q: Which draws more current, a 60-W or a 100-W incandescent lamp, both rated for 120-V operation? A) 60-W lamp B) 100-W lamp C) both the same

Q: Which has the larger resistance, a 60-W or a 100-W incandescent lamp, both rated for 120-V operation? A) 60-W lamp B) 100-W lamp C) both the same

Q: The power dissipated in a 4-ohm resistor carrying 3 A is A) 7 W. B) 18 W. C) 36 W. D) 48 W. E) not enough information

Q: What is the power rating of a device that draws 0.8 A when connected to 120 V? A) 12 W B) 15 W C) 60 W D) 96 W E) 120 W

Q: The current in a 100-W bulb connected to a 120-V source is A) 0.5 A. B) 1.2 A. C) 12,000 A. D) none of the above

Q: The electric power of a lamp that carries 2 A at 120 V is A) 1/6 W. B) 2 W. C) 60 W. D) 20 W. E) 240 W.

Q: The unit of measurement for electric power is A) joules per second. B) watts. C) both are equivalent D) none of the above

Q: Three resistors take the shape of a triangle, one resistor in each leg. Resistance in one leg is 4 ohms, in a second leg is 6 ohms, and third leg is 10 ohms. A measurement of resistance across the 10-ohm resistor will show the equivalent resistance to be A) 1.4 ohms. B) 5 ohms. C) 6.7 ohms. D) greater than 6.7 ohms.

Q: Three 10-ohm resistors take the shape of a triangle, one resistor in each leg. An ohm-meter across any two points of the triangle will show the equivalent resistance to be A) 1.4 ohms. B) 5 ohms. C) 6.7 ohms. D) greater than 6.7 ohms.

Q: A 4-ohm and 6-ohm resistor connected in parallel have an equivalent resistance of A) 2.4 ohms. B) 4 ohms. C) 5 ohms. D) 5.5 ohms. E) 10 ohms.

Q: A pair of 1-ohm resistors connected in series is 2 ohms, and when connected in parallel is A) 1/2 ohm. B) 1 ohm. C) also 2 ohms. D) none of the above

Q: The equivalent (combined) resistance of 1-ohm, 2-ohm, and 3-ohm in parallel is about A) 0.06 ohm. B) 1 ohm. C) 1.8 ohms. D) 6 ohms. E) 9 ohms.

Q: The equivalent (combined) resistance of 1-ohm, 2-ohm, and 3-ohm in series is about A) 1 ohm. B) 1.8 ohms. C) 6 ohms. D) 9 ohms.

Q: The equivalent resistance of resistors connected in series in a circuit is A) often less than the resistance of the lowest resistor. B) always less than the resistance of the lowest resistor. C) usually half the value of the lowest resistor. D) none of the above

Q: The equivalent resistance of any parallel branch in a circuit is A) often less than the resistance of the lowest resistor. B) always less than the resistance of the lowest resistor. C) usually half the value of the lowest resistor. D) none of the above

Q: To achieve a low equivalent resistance for a pair of resistors, connect them in A) series. B) parallel. C) either of these

Q: To achieve a high equivalent resistance for a pair of resistors, connect them in A) series. B) parallel. C) either of these

Q: Compared to the amount of electric current in the filament of a lamp, the amount of current in the connecting wire is A) definitely less. B) often less. C) actually more. D) the same. E) incredibly, all of the above

Q: The headlights, radio, and defroster fan in an automobile are connected in A) series. B) parallel. C) order of energy efficiency.

Q: More toll booths on a highway is analogous to a A) series circuit. B) parallel circuit. C) complex combination of both of these

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

Q: As more lamps are put into a parallel circuit, the overall current in the power source A) increases. B) decreases. C) remains the same.

Q: As more lamps are put into a series circuit, the overall current in the power source A) increases. B) decreases. C) stays the same.

Q: A pair of 1-ohm resistors connected in parallel has a combined resistance of A) 1 ohm. B) 2 ohms. C) 1/2 ohm. D) none of the above

Q: A pair of 1-ohm resistors connected in series has a combined resistance of A) 1 ohm. B) 2 ohms. C) 1/2 ohm. D) none of the above

Q: The safety fuse in an electric circuit is properly connected in A) series with the circuit. B) parallel to the circuit. C) either of these

Q: When two light bulbs are connected in parallel to a battery, the electric resistance that the battery senses is A) greater than the resistance of either bulb. B) less than the resistance of either bulb. C) none of the above

Q: When two bulbs are connected in series to a battery, the electric resistance that the battery senses is A) greater than the resistance of either bulb. B) less than the resistance of either bulb. C) none of the above

Q: Two light bulbs, a thick-filament one and a thin-filament one, are connected in series to a battery. The voltage is greater across the lamp with the A) thick filament. B) thin filament. C) same for both

Q: Two light bulbs, a thick-filament one and a thin-filament one, are connected in parallel to a battery. The voltage is greater across the lamp with the A) thick filament. B) thin filament. C) same for each

Q: Two lamps, a thick-filament one and a thin-filament one, are connected in parallel to a battery. The current is greater in the lamp with the A) thick filament. B) thin filament. C) same in each

Q: Two lamps, a thick-filament one and a thin-filament one, are connected in series to a battery. The current is greater in the lamp with the A) thick filament. B) thin filament. C) same in each

Q: Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will draw A) more current. B) less current. C) the same current.

Q: Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will draw A) more current. B) less current. C) the same current.

Q: Compared to the amount of current that flows from a battery and into a circuit, the amount of current that returns to the battery is A) less. B) the same. C) greater. D) dependent on the internal resistance of the battery.

Q: Strictly speaking, it is correct to say that voltage A) flows through a circuit. B) flows across a circuit. C) is impressed across a device in a circuit. D) all of these

Q: Strictly speaking, it is correct to say that A) charge flows through a circuit. B) voltage flows through a circuit. C) resistance is established across a circuit. D) current causes voltage. E) all of these

Q: The current through two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is A) 22 ohms. B) 44 ohms. C) 220 ohms. D) 440 ohms. E) none of the above

Q: If you plug a 110-V electric toaster into a 220-V outlet, current in the toaster will be about A) half what is should be. B) the same as if it were plugged into a 110-V outlet. C) more than twice what it should be. D) twice what it should be.

Q: An electrical device that is "grounded" has A) no potential difference between it and the ground. B) an infinite potential difference between it and the ground. C) a firm connection to the ground. D) low voltage.

Q: The purpose of the third prong on a common electric plug of an appliance is A) to handle three-phase electricity. B) to provide an alternate live wire. C) to connect the appliance to zero ground potential. D) a substitute for a safety fuse. E) all of the above

Q: A bird can sit harmlessly on a high-voltage wire because A) the wire is insulated. B) no potential difference is across the birds feet. C) current is inside, not outside, the wire. D) the net charge on a current-carrying wire is zero. E) all of the above

Q: The damage of electrical shock is predominantly due to A) excess current. B) an absence of voltage. C) reduced resistance. D) none of the above

Q: When Eddie Electron experiences an electrical shock, the source of electrons composing the shock is A) the ground beneath Eddie's feet. B) Eddie's body. C) the power plant. D) whatever electric device being handled. E) electric field in the air.

Q: The value of a resistor that carries 2 A when connected to 10 V is A) 2 ohms. B) 5 ohms. C) 10 ohms. D) 20 ohms. E) more than 20 ohms.

Q: The voltage across a 10-ohm resistor carrying a current of 5 A is A) 2 V. B) 5 V. C) 10 V. D) 20 V. E) more than 20 V.

Q: The current through a 10-ohm resistor connected to a 120-V power supply is A) 1 A. B) 10 A. C) 12 A. D) 120 A. E) none of the above

Q: Electrical resistance is greater for A) dry skin. B) wet skin. C) both the same

Q: When a steady voltage is across one-half as much resistance, the current A) is half. B) remains the same. C) is doubled. D) is quadrupled.

Q: When the voltage across a steady resistance is doubled, the current A) is half. B) remains the same. C) is doubled. D) is quadrupled.

Q: Current in a conductor can be increased by A) increasing the voltage across it. B) reducing its resistance. C) both of these D) neither of these

Q: Ohm's law tells us that the amount of current produced in a circuit is A) directly proportional to voltage. B) inversely proportional to resistance. C) both of these D) neither of these

Q: The electric resistance of a superconductor is A) zero. B) infinite. C) usually lower than ordinary resistors. D) none of the above

Q: More current will occur in a lamp when its filament is A) cold. B) hot. C) either cold or hot.

Q: Heat a copper wire and its electrical resistance A) decreases. B) remains unchanged. C) increases.

Q: A length of wire has resistance R. The same kind of wire twice as long has resistance A) R/2. B) R. C) 2R. D) none of the above

Q: Which of these, both of the same length, has the greater electrical resistance? A) a thick copper wire B) a thin copper wire C) both about the same D) need more information

Q: Which of these, all of the same length, has the greater electrical resistance? A) a copper rod B) an iron rod C) a rubber rod D) all about the same E) none of the above

Q: Electrical resistance is normally measured in A) amperes. B) volts. C) newtons. D) joules. E) none of the above

Q: The unit of resistance is named after A) Isaac Newton. B) Benjamin Franklin. C) Georg Simon Ohm. D) Micheal Faraday. E) Charles Coulomb.

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