Chapter 13- Electric Circuits

A 19-Ω resistor has a voltage difference of 7 V across its leads. (a) What is the current through the resistor? (b) What is the power being dissipated in this resistor?

(a) 0.368 A (b) 2.58 W

In the circuit shown below, the r = 2-Ω resistance is the internal resistance of the battery and can be considered to be in series, as shown, with the battery and the R = 7-Ω load. (Let = 4 V.) (a) What is the current flowing through the 7-Ω resistor? (b) What is the voltage difference across the 7-Ω resistor?

(a) 0.444 A (b) 3.11 V

A toaster draws a current of 3 A when it is connected to a 220-V ac line. (a) What is the power consumption of this toaster? (b) What is the resistance of the heating element in the toaster?

(a) 660 W (b) 73.3 Ω

Two resistors are connected in series with a battery as shown in the diagram below. R1 is greater than R2. (a) Which of the two resistors, if either, has the greater current flowing through it? a. R1 carries a greater current. b. R2 carries a greater current. c. The current is the same in each. (b) Which of the two resistors, if either, has the greater voltage difference across it? a. The voltage difference is greater across R1. b. The voltage difference is greater across R2. c. The voltage is the same across each.

(a) c. The current is the same in each. (b) a. The voltage difference is greater across R1.

A current of 3.5 A is flowing through a resistance of 29 Ω. What is the voltage difference across this resistance?

101.5 v

Two resistors, each having a resistance of 13 Ω, are connected in parallel. What is the equivalent resistance of this combination?

6.5 Ω

An ohm is equal to which of these? a. a volt per ampere b. a coulomb per second c. an ampere per second d. a volt

a. a volt per ampere

Two arrangements of a battery, bulb, and wire are shown below. Which of the two arrangements, if either, will light the bulb? Explain. a. arrangement (a) b. arrangement (b) c. neither arrangement d. both arrangements

a. arrangement (a)

A 12 ohm resistor and a 24 ohm resistor are connected in parallel across a 6.0 V battery. The correct statement from the following is a. the voltage difference between the ends of each resistor is the same. b. the power dissipated is the same in each resistor. c. the larger current is in the larger resistor. d. the current is the same in each resistor.

a. the voltage difference between the ends of each resistor is the same.

A heater is rated to dissipate 1800 W when connected to a 120 V source. The current drawn by the device is a. 30 A. b. 15 A. c. 120 A. d. 0.067 A. e. 1800 A.

b. 15 A.

A household circuit rated at 120 Volts is protected by a fuse rated at 15 amps. What is the maximum number of 100 watt light bulbs which can be lit simultaneously in parallel in this circuit without blowing the fuse? a. 24 b. 18 c. 8 d. 4 e. 20

b. 18

A certain kind of light bulb carries 1.5 amperes of current when connected to a 120 Volt AC circuit. What is its power rating? a. 100 W b. 180 W c. 240 W d. 80 W

b. 180 W

If the current through a certain resistance is doubled, does the power dissipated in that resistor also double? Explain. a. Yes, the power dissipated will double because it is proportional to the current. b. No, the power dissipated will quadruple because it is proportional to the square of the current. c. No, the power dissipated will be half of the original because it is proportional to the inverse of the current. d. No, the power dissipated will be one-fourth of the original because it is proportional to the inverse of the square of the current.

b. No, the power dissipated will quadruple because it is proportional to the square of the current.

Two circuit diagrams are shown below. Which one, if either, will cause the light bulb to light? a. Only the bulb in diagram (a) will light. b. Only the bulb in diagram (b) will light. c. The bulbs in both diagram (a) and (b) will light. d. The bulbs in neither diagram (a) nor (b) will light.

b. Only the bulb in diagram (b) will light.

A 40 W bulb and a 60 W bulb are connected in series with a 120 V power source. Which of the following is true for this arrangement? a. The 60 W bulb is brighter than it would be if the 40 W bulb were replaced by a wire. b. The 40 W bulb is brighter than the 60 W bulb. c. The 60 W bulb is brighter than the 40 W bulb. d. The 40 W bulb is brighter than it would be if the 60 W bulb were replaced by a wire.

b. The 40 W bulb is brighter than the 60 W bulb.

If we disconnect R2 from the rest of the circuit shown in the diagram, will the current through R3 increase, decrease, or remain the same? Explain. a. The current in R3 will increase because disconnecting R2 will result in a smaller total resistance in the circuit. b. The current in R3 will decrease because disconnecting R2 will result in a larger total resistance in the circuit. c. The current in R3 will remain the same because disconnecting R2 does not change the total resistance in the circuit.

b. The current in R3 will decrease because disconnecting R2 will result in a larger total resistance in the circuit.

The potential difference across the terminals of a storage battery not connected in any circuit is observed to be 12 V. When it is connected to an external resistance the potential difference across the terminals is observed to be 11 V while the current in the external resistance is 2 A. What is the internal resistance of the battery? a. zero b. 1.0 ohm c. 0.50 ohms d. 5.5 ohms e. 2.0 ohms

c. 0.50 ohms

Three identical resistors can be connected in any combination. It's not necessary to include all three in any given combination. The number of distinct values of resistance that can be made is a. three. b. four. c. five. d. six or more. e. two or fewer.

d. six or more.

The unit for electromotive force (emf) is a. A. b. ohm. c. N/C. d. N. e. V.

e. V.