### Parallel Circuits

1. A 470 Ω resistor, a 220 Ω resistor, and a 100 Ω resistor are all in parallel. The total resistance is approximately

1. 790 Ω
2. 470 Ω
3. 60 Ω
4. 30 Ω

60 Ω

2. A set of Christmas tree lights is connected in parallel across a 110 V source. The filament of each light bulb is 1.8 k. The current through each bulb is approximately

1. 610 mA
2. 18 mA
3. 110 mA
4. 61 mA

61 mA

3. A sudden increase in the total current into a parallel circuit may indicate

1. a drop in source voltage
2. an open resistor
3. an increase in source voltage
4. either a drop in source voltage or an open resistor

an increase in source voltage

4. An ammeter has an internal resistance of 50 Ω. The meter movement itself can handle up to 1 mA. If 10 mA is applied to the meter, the shunt resistor, RSH1, is approximately

1. 55 Ω
2. 5.5 Ω
3. 50 Ω
4. 9 Ω

5.5 Ω

5. Five 100 Ω resistors are connected in parallel. If one resistor is removed, the total resistance is

1. 25 Ω
2. 500 Ω
3. 100 Ω
4. 20 Ω

25 Ω

6. Five light bulbs are connected in parallel across 110 V. Each bulb is rated at 200 W. The current through each bulb is approximately

1. 2.2 A
2. 137 mA
3. 1.8 A
4. 9.09 A

1.8 A

7. Four 8 Ω speakers are connected in parallel to the output of an audio amplifier. If the maximum voltage to the speakers is 12 V, the amplifier must be able to deliver to the speakers

1. 18 W
2. 1.5 W
3. 48 W
4. 72 W

72 W

8. Four equal-value resistors are connected in parallel. Ten volts are applied across the parallel circuit and 2 mA are measured from the source. The value of each resistor is

1. 12.5 Ω
2. 200 Ω
3. 20 KΩ
4. 50 Ω

20 KΩ

9. Four resistors are connected in parallel. Fifteen mA flows through resistor R. If the second resistor is 2R, the third resistor 3R, and the fourth resistor 4R, the total current in the circuit is

1. 60 mA
2. 15 mA
3. 135 mA
4. 31.25 mA