Series Circuits and Parallel Circuits

The picture shows an electrical circuit. This circuit is a series circuit because: 

• It has 3 light bulbs.
• The same current flows through all three light bulbs.
• It uses a single battery.
• The electrical current is divided between the three light bulbs.

In a parallel circuit if one of the light bulbs burns out the rest _________.

• stop the flow of electricity

•  can still light up

•  will go out

• of the light bulbs burn out also

The equivalent resistance (total resistance) for the circuit shown is ___.

• 0.333 ohms

• 3 ohms

• 31 ohms

• 10 ohms

• 6 ohms

The equivalent resistance (total resistance) for the circuit shown is ___.

• 0.333 ohms

• 3 ohms

• 31 ohms

• 25 ohms

• 15 ohms

In order to have current flow, it is necessary to have ___.

• a source of potential difference and some resistance

• a complete closed path for charge and a switch

• a complete closed path for charge and some resistance

• a source of potential difference and a complete closed path for charge

• some resistance and a way to calculate power

Three 9-ohm resistors connected in series have a total resistance of ___.

• 27 ohms

• 9 ohms

• 3 ohms

• 18 ohms

• 4.5 ohms

Three 9-ohm resistors connected in parallel have a total resistance of ___.

• 27 ohms

• 3 ohms

• 18 ohms

• 4.5 ohms

If a 12-W light bulb has 6 V of potential difference placed across it, the current flowing through it is ___.

• 0.5 A

• 6 A

• 2 A

• 72 A

• 3 A

If the voltage across a circuit of constant resistance is doubled, the power dissipated by that circuit will

• be four times as large.

• be two times as large.

• decrease to one-half the original power.

• decrease to one-fourth the original power.

An instrument is rated at 240 W if it is connected across a 120-V dc power supply.

(a) What current does it draw under normal operation?

(b) What is its resistance?

• (a) 0.20 A (b) 360 Ω

• (a) 60 A (b) 2.0 Ω

• (a) 2.0 A (b) 60 Ω

• (a) 0.2 A (b) 60 Ω