Circuits (mixed)

A 4 ohm resistor and a 8 ohm resistor are connected in series. If the current throughout the 4 ohm resistor is 2 amperes, the current through the 8 ohm resistor is

• 1A
• 2 A
• 0.5 A
• 4 A

If a 15 ohm resistor is connected in parallel with a 30 ohm resistor, the equivalent resistance is

• 15
• 2.0
• 10
• 45

In which electric circuit would the voltmeter read 10 volts?

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In an operating electrical circuit, the source of potential difference could be

• a voltmeter
• a battery
• an ammeter
• a resistor

The diagram below represents a 3.0-ohm resistor connected to a 12-volt battery. Meters X and Y are correctly connected in the circuit.

• X = 12 V and Y = 0.25 A
• X = 12 V and Y = 4.0 A
• X = 0.25 A and Y = 12 V
• X = 4.0 A and Y = 12 V

An electric circuit contains a battery, three lamps, and an open switch, as represented in the diagram below. When the switch is open, there is an electric current in

• lamp I, only
• lamps II and III, only
• lamps I, II, and III
• none of the lamps

When only one lightbulb blows out, an entire string of decorative lights goes out. The lights in this string must be connected in

• parallel with one current pathway
• parallel with multiple current pathways
• series with one current pathway
• series with multiple current pathways

Which circuit has the largest equivalent resistance?

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The diagram below represents a circuit consisting of two resistors connected to a source of potential difference. What is the current through the 20.-ohm resistor?

• 0.25 A
• 6.0 A
• 12 A
• 4.0 A