Electricity and Circuits Practice Test ANSWERS

1) A coulomb per second is the same asA) a watt.B) an ampere.C) a volt-second.D) a volt per second.

Answer: BDiff: 1 Page Ref: Sec. 18.2

2) Consider two copper wires. One has twice the length and twice the cross-sectional area of the other. How do the resistances of these two wires compare?

A) Both wires have the same resistance.B) The longer wire has twice the resistance of the shorter wire.C) The longer wire has four times the resistance of the shorter wire.D) none of the given answers

Answer: ADiff: 2 Page Ref: Sec. 18.4

3) If the resistance in a circuit with constant current flowing is doubled, the power dissipated by that circuit will

A) quadruple.B) double.C) decrease to one half.D) decrease to one fourth.

Answer: BDiff: 1 Page Ref: Sec. 18.5-18.6

4) What current is flowing if 4.0 x 1016 electrons pass a point in 0.50 s?A) 0.013 AB) 0.31 AC) 6.3 AD) 78 A

Answer: ADiff: 2 Page Ref: Sec. 18.2

5) A coffee maker, which draws 13.5 A of current, has been left on for 10 min. What is the net number of electrons that have passed through the coffee maker?

A) 1.5 x 1022

B) 5.1 x 1022

C) 1.8 x 103

D) 8.1 x 103

Answer: BDiff: 2 Page Ref: Sec. 18.2

6) A 4000-Ω resistor is connected across 220 V. What current will flow?A) 0.055 AB) 1.8 AC) 5.5 AD) 18 A

Answer: ADiff: 1 Page Ref: Sec. 18.3

7) What is the resistance of a circular rod 1.0 cm in diameter and 45 m long, if the resistivity is 1.4 x 10-8 Ωm?

A) 0.0063 ΩB) 0.0080 ΩC) 0.80 ΩD) 6.3 Ω

Answer: BDiff: 2 Page Ref: Sec. 18.4

8) A 1.0-m length of nichrome wire has a radius of 0.50 mm and a resistivity of 100 x 10-8 Ωm. If the wire carries a current of 0.50 A, what is the voltage across the wire?

A) 0.0030 VB) 0.32 VC) 0.64 VD) 1.6 V

Answer: CDiff: 2 Page Ref: Sec. 18.4

9) A 110-V hair dryer is rated at 1200 W. What current will it draw?A) 0.090 AB) 1.0 AC) 11 AD) 12 A

Answer: CDiff: 1 Page Ref: Sec. 18.5-18.6

10) The monthly (30 days) electric bill included the cost of running a central air-conditioning unit for 2.0 hr/day at 5000 W, and a series connection of ten 60 W light bulbs for 5.0 hr/day. How much did these items contribute to the cost of the monthly electric bill if electricity costs 8.0¢ per kWh?

A) $21.30B) $31.20C) $13.20D) $12.30

Answer: BDiff: 2 Page Ref: Sec. 18.5-18.6

11) When resistors are connected in series,A) the same power is dissipated in each one.B) the potential difference across each is the same.C) the current flowing in each is the same.D) More than one of the given answers is true.

Answer: CDiff: 1 Page Ref: Sec. 19.2

12) When resistors are connected in parallel, we can be certain thatA) the same current flows in each one.B) the potential difference across each is the same.C) the power dissipated in each is the same.D) their equivalent resistance is greater than the resistance of any one of the individual resistances.

Answer: BDiff: 1 Page Ref: Sec. 19.2

13) Four resistors of 12, 3.0, 5.0, and 4.0 Ω are connected in series. A 12-V battery is connected to the combination. What is the current through the battery?

A) 0.50 AB) 1.0 AC) 1.5 AD) 2.0 AAnswer: A

Diff: 2 Page Ref: Sec. 19.2

14) A 22-A current flows into a parallel combination of 4.0 Ω, 6.0 Ω, and 12 Ω resistors. What current flows through the 12- Ω resistor?

A) 18 AB) 11 AC) 7.3 AD) 3.7 A

Answer: DDiff: 2 Page Ref: Sec. 19.2

15) A combination of 2.0 Ω in series with 4.0 Ω is connected in parallel with 3.0 Ω. What is the equivalent resistance?

A) 2.0 ΩB) 3.0 ΩC) 4.0 ΩD) 9.0 Ω

Answer: ADiff: 2 Page Ref: Sec. 19.2

16) Three resistors of 4.0, 6.0, and 10.0 Ω are connected in parallel. If the combination is connected in series with a 12.0-V battery and a 2.0- Ω resistor, what is the current through the 10.0- Ω resistor?

A) 0.59 AB) 2.7 AC) 11.2 AD) 16.0 A

Answer: ADiff: 2 Page Ref: Sec. 19.2

17) A 3.0-Ω resistor is connected in parallel with a 6.0- Ω resistor. This combination is connected in series with a 4.0- Ω resistor. The resistors are connected to a 12-volt battery. How much power is dissipated in the 3.0- Ω resistor?

A) 2.7 WB) 5.3 WC) 6.0 WD) 12 W

Answer: BDiff: 3 Page Ref: Sec. 19.2

18) If E = 40 V, what is the voltage on R1 in the Figure?A) 6.7 VB) 8.0 VC) 10 VD) 20 V

Answer: BDiff: 2 Page Ref: Sec. 19.2

19) If E = 100 V, what is the voltage across R5 in the Figure?A) 19 VB) 40 VC) 75 VD) 77 V

Answer: ADiff: 3 Page Ref: Sec. 19.2