Series and Parallel Circuits

Series Circuits

•Current can only travel through one path

•Current is the same through all parts of the circuit.

•The sum of the voltages of each component of the circuit must equal the battery.

•The equivalent resistance of a series circuit is the sum of the individual resistances.

Subject | Subject

Parallel Circuits

•Current splits into “branches” so there is more than one path that current can take

•Voltage is the same across each branch

•Currents in each branch add to equal the total current through the battery​

Subject | Subject

You might want to connect two lightbulbs to a D-cell. How can you do this? There are two ways. You can open the one-lightbulb circuit and put a second lightbulb into the circuit. Now the electric current flows through two lightbulbs in one circuit. This is a series circuit. There are two lightbulbs and one D-cell connected in series. In a series circuit, current has only one pathway to flow from the source (D-cell) to the components (lightbulbs).

Two lightbulbs in series

There is another way to add a second lightbulb to the one-lightbulb circuit. You can use two wires to connect the second lightbulb to the first lightbulb. This is called a parallel circuit. There are two lightbulbs in parallel connected to a D-cell. In this parallel circuit,

each component (lightbulb) has its own pathway to the energy source (D-cell). Lightbulb 1 is in the blue-arrow pathway; lightbulb 2 is in the red-arrow pathway.

Two lightbulbs in parallel

​

Suppose you want to light two lightbulbs. Is there any reason to put them in parallel rather than in series? Yes. The reason becomes clear when you compare the two kinds of circuits. Two lightbulbs in series both shine with a dim light. Both lightbulbs in parallel shine brightly. If you want bright lights, put the lightbulbs in parallel.

​​Which circuit should you use?

​

Two lightbulbs in series have to share the energy of the D-cell. There is only one pathway for the electric current. The current flows from the negative end of the cell through the first lightbulb. It then goes through the second lightbulb and back to the positive end of

the cell.

​​Why is there a difference?

​

Two lightbulbs in parallel do not have to share energy of the D-cell. Each lightbulb has its own pathway to the source of electricity. Even though some wires are shared for part of the pathway, more than one pathway lets each lightbulb gets its own electricity. That's why lightbulbs in parallel shine more brightly.

So, is it better to connect your lightbulbs in series or in parallel? It seems like parallel would be better because you get two bright lights. But there is a cost. The energy of the D-cell will drain much faster when it is supplying electricity to two lightbulbs in parallel. When lightbulbs are connected in series, the D-cell lasts longer, but the lights are dimmer.

If you want to put two or more D-cells in a circuit, they can be connected in series or in parallel. Which of these circuits shows two cells in series? Which shows two cells in parallel?

In circuit 1, cells A and B are in parallel. Each cell delivers electricity to the lightbulb in its own pathway. In circuit 2, electricity is delivered to the lightbulb by two cells working together in the same pathway. As a result, the lightbulb in circuit 2 will be twice as bright as the lightbulb in circuit 1.

​​Adding More D-Cells to a Circuit

​

Here is an interesting circuit made with lightbulbs and D-cells. How would you describe this circuit?

This circuit is one lightbulb in parallel with two lightbulbs in series, powered by two D-cells in parallel. If you said that, you got it right.

​

Multiple Choice

This is an example of a _______ circuit

• open
• series
• parallel
• square

Multiple Choice

This is an example of a ______ circuit

• Series
• Parallel
• Open
• Dihexihedral

Multiple Choice

What kind of circuit is this?

• Series
• Consecutive
• Parallel
• Training

Multiple Choice

What kind of circuit is this?

• Series
• Consecutive
• Parallel
• Training

Multiple Choice

What 'flows' in a wire?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

What particle has a negative charge?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

In a parallel circuit, if one connection is broken, all of the connections stop working.

• True
• False

Multiple Choice

A series circuit has ____ path(s) that the electric current can take. 

• One
• Two 
• Three 
• Four

Multiple Choice

This circuit has more than one loop. When one light goes out, the others stay on. 

• closed circuit
• series circuit
• parallel circuit
• open circuit

Multiple Choice

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

Multiple Choice

what is this symbol for?

• light bulb
• switch
• battery
• resistor

Multiple Choice

The equivalent resistance in this circuit is 

• 100 ohms
• 450 ohms
• 400 ohms
• 30 ohms

Multiple Choice

Does this statement best describe a parallel or a series circuit.
 
When more light bulbs are added they all remain bright. 

• Parallel circuit
• Series circuit

Multiple Choice

What does the resistance of a wire tell you?

• The speed of electron flow through it.
• How tough it is for electrons to flow through it.
• The amount of energy given to the electrons.
• The amount of energy taken away from the electrons.

Multiple Choice

A class prepared some electrical circuits using battery, connecting wires, and three light bulbs.  Which of these circuits can make the three bulbs light?

• A
• B
• C
• D

Multiple Choice

Unit for resistance

• Ampere
• Ohm
• Volt
• Watt

Multiple Choice

Unit for current

• Ohm
• Ampere
• Volt
• Watt

Multiple Choice

In a cell, which form of energy is converted into electrical energy?

• Chemical energy
• Solar energy
• Mechanical energy
• Electrical energy

Multiple Choice

What is the total resistance of three 10,000 Ω resistors in series?

• 300,000 Ω

• 3,000 Ω

• 30,000 Ω

• 3.0*10^6 Ω

Multiple Choice

What is the equivalent resistance of three 10,000 Ω resistors in parallel?

• 33,333 Ω

• 3.1*10^7 Ω

• 3.33333*10^14 Ω

• 3,333.3 Ω

Multiple Choice

Suppose you have a 100 Ω resistor parallel to two 100 Ω resistors in series. what is their total resistance?

• 66.7 Ω

• 300 Ω

• 69.69 Ω

• 600 Ω

Multiple Choice

Resistance?

• 1/Rp = (1/5) + (1/8) + (1/3)

• 120 Ω

• 1.5189873 Ω

• 1/Rp = (1/5) * (1/8) * (1/3)

Multiple Choice

• Series circuit - Bulbs are lit
• Series circuit - Bulbs are off
• Parallel circuit - Bulbs are lit
• Parallel circuit - Bulbs are off

Multiple Choice

• Bulbs are in parallel - Circuit X is brighter than Circuit Y
• Bulbs are in parallel - Circuit Y is brighter than Circuit X
• Bulbs are in series - Circuit X is brighter than Circuit Y
• Bulbs are in series - Circuit Y is brighter than Circuit X

Multiple Choice

This circuit does not work because…

• the bulbs are not connected properly
• two cells are not powerful enough
• there is a break in the circuit
• the cells are facing each other

Multiple Choice

• Circuit X is brighter than circuit Y
• Circuit Y is brighter than circuit X
• Both circuits have the same brightness
• Neither circuit will light the bulbs

Multiple Choice

• X = OFF
  Y = OFF
• X = ON
  Y = OFF
• X = OFF
  Y = ON
• X = ON
  Y = ON

Multiple Choice

when the switch is closed.....

• both bulbs TURN ON
• both bulbs STAY ON
• both bulbs TURN OFF
• both bulbs STAY OFF

Multiple Choice

This circuit won't work. What essential part is missing from this circuit?

• resistance
• source of electric current
• conductor
• ammeter

Multiple Choice

The force that pushes the electricity through a circuit is called...

• resistance
• voltage
• current
• switch

Multiple Choice

The flow of electricity through a conductor is called...

• resistance
• voltage
• current
• source of electric current

Multiple Choice

The best conductors for electricity are made of...

• wood
• plastic
• rubber
• metal

Multiple Choice

This measures the speed of the current in a circuit

• voltage
• ammeter
• switch
• resistance

Multiple Choice

What slows down the flow of electricity in a circuit?

• resistance
• voltage
• current
• source of electric current

Multiple Choice

Which circuit (s) are parallel?

• A
• A and B
• B and C
• C

Multiple Choice

Which one will still function if one light bulb goes out?

• A-Series
• B-Parallel
• A-Parallel
• B-Seriese

Multiple Choice

If I add more light bulbs to a series circuit what happens?

• The current speeds up and the lights get brighter
• The current slows down and the lights dim lower
• The current speeds up and the lights dim lower
• The current slows down and the lights get brighter

Multiple Choice

A series circuit has ____ path(s) that the electric current can take. 

• One
• Two 
• Three 
• Four

Multiple Choice

In a parallel circuit, if one connection is broken, all of the connections stop working.

• True
• False

Multiple Choice

An object through which electrons can easily flow is called a(n) ___________.

• Conductor
• Insulator

Multiple Choice

What kind of circuit is this?

• series
• parallel

Multiple Choice

this is the symbol for a _____?

• switch
• light 
• battery
• wires

Multiple Choice

What kind of circuit is this?

• Series
• Consecutive
• Parallel
• Training

Multiple Choice

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 has more than one path to flow through

Multiple Choice

What is a Parallel circuit? 

• Has only one path 
• Has more than one path 
• Allows energy to travel through easily 
• Has only one light bulb

Multiple Choice

What is a switch's function in a circuit?

• to make the current hotter or colder
• turn on and off the flow of current
• the pathway that current flows
• to add more power to the circuit

Multiple Choice

this circuit is .....?

• open
• parallel
• closed
• The cutest little circuit evah!

Multiple Choice

What is a circuit?

• A constant flow of electricity 
• A path that a current can flow along

Multiple Choice

If the electric circuit is CLOSED, the switch is _______. 

• ON
• OFF

Multiple Choice

This is an example of a _______ circuit

• open
• series
• parallel
• square

Multiple Choice

This is an example of a ______ circuit

• Series
• Parallel
• Open
• Dihexihedral

Multiple Choice

wood is a _____?

• conductor
• insulator

Multiple Choice

brass is a _____?

• insulator
• conductor

Multiple Choice

what is this symbol for?

• light bulb
• switch
• battery
• resistor

Multiple Choice

If the electric circuit is OPEN, the switch is ____.

• ON
• OFF

Multiple Choice

Why electrical wiring usually are covered with a layer of plastic?

• To make it look pretty

• To help electricity flow along the wire

• To make it safe

• To add more energy

Multiple Choice

1. Which switch or switches must be closed to make the lamps light?

• Only switch 1

• Only switch 1

• Switches 1 and 2

• Switches 1 , 2 and 3

Multiple Choice

Placing an ammeter at different positions in a series circuit will give you different readings. True or false?

• true

• false

Multiple Choice

In the circuit shown, ammeter 1 reads 1.0 A. What does ammeter 2 read?

Include the unit symbol A in your answer. Give your answer to 2 significant figures.

• 1.0 A

• 1.0 a

• 1.00 A

• 1.0 amps

Multiple Choice

A circuit diagram uses circuit symbols to represent components and straight lines to represent wires. Which of these is the correct circuit diagram for the circuit shown?

• A

• B

• C

• D

Multiple Choice

In a series circuit, there is only one path for the electricity to take. Which of these circuits are series circuits?

• A & B

• A & C

• C & D

• B & D

Multiple Choice

In a parallel circuit, there is more than one path for the electricity to take. Which of these circuits are parallel circuits?

• A & B

• A & C

• C & D

• B & D

Multiple Choice

Which circuit diagram shows two lamps connected in series?

• A

• B

• C

• D

Multiple Choice

Which circuit diagram shows two lamps connected in parallel?

• A

• B

• C

• D

Multiple Choice

Which circuit diagram shows a lamp, motor and switch connected in series?

• A

• B

• C

• D

Multiple Choice

Which circuit diagram shows two lamps connected to each other in series and a motor connected to the two lamps in parallel?

• A

• B

• C

• D

Multiple Choice

Which circuit diagram shows a circuit where the lamp and the motor can be controlled by one switch?

• A

• B

• C

Multiple Choice

Which circuit diagram shows a circuit where the lamp and the motor can be controlled independently?

• A

• B

• C

Multiple Select

Three lamps and three switches are connected in parallel. Which lamp or lamps light up when switch A is closed?

• Lamp 1

• Lamp 2

• Lamp 3

Multiple Choice

Three lamps and three switches are connected in parallel with a cell. Which lamp or lamps light up when switches A and B are closed?

• Lamp 1

• Lamp 2

• Lamp 3

Multiple Select

Three lamps and three switches are connected in parallel with a cell. Which switch or switches need to be closed to light up all three lamps at the same time?

• switch A

• switch B

• switch C

Multiple Choice

In a parallel circuit, the current splits between the branches. The sum of the currents in each branch is equal to the total current leaving the cell. If ammeters 3 and 4 both read 0.5 A, what does ammeter 1 read?

Include the unit symbol A in your answer. Give your answer to 2 significant figures.

• 1.0 amps

• 1.00 A

• 0.5 A

• 1.0 A

Multiple Choice

The current is the same at all points in a parallel circuit. True or false?

• True

• False

Multiple Choice

In the circuit shown, all three ammeters read 0.1 A. If lamp 1 breaks, what will the new reading on ammeter 1 be?

• 0 A

• 0.1 A

• 0.2 A

Multiple Choice

In the circuit shown, ammeters 1 and 3 both read 1.5 A. What does ammeter 2 read?

Include the unit symbol A in your answer. Give your answer to 2 significant figures.

• 1.50 A

• 1.5 A

• 1.5 a

• 1.5 amps

Multiple Choice

In a parallel circuit, the current splits between the branches. The sum of the currents in each branch is equal to the total current leaving the cell. If ammeters 1 and 2 both read 2.0 A, and ammeter 3 reads 1.0 A, what does ammeter 4 read?

• 2.0 A

• 1.0 A

• 1.0

• 1 a

Multiple Choice

Which of these statements is true for a series circuit?

• The voltage across each component is the same as the voltage supplied.

• The total voltage supplied is shared between the components.

Multiple Choice

The number of cells in a circuit affects the voltage. What happens to the voltage when a second cell is added in the same direction as the first cell?

• The voltage decreases.

• The voltage stays the same.

• The voltage increases.

Multiple Choice

Which circuit shows a voltmeter correctly wired to measure the voltage across the lamp?

• A

• B

• C

Multiple Choice

In a series circuit, the voltage is split between the components. The sum of the voltages across the components is equal to the voltage supplied by the battery. What is the reading on voltmeter 2?

• 1

• 2

• 1.0

• 1.00

Multiple Choice

What is the reading on voltmeter 1 in the circuit shown?

Don't include units in your answer. Give your answer to 2 significant figures.

• 7.5

• 2.5

• 2.50

Multiple Choice

In a parallel circuit, the voltage supplied by the battery is equal to the voltage across each branch. What is the reading on voltmeter 2?

Don't include units in your answer. Give your answer to 2 significant figures.

• 3

• 3.0

• 3.00

Multiple Choice

In a parallel circuit, the voltage supplied by the battery is equal to the voltage across each branch. What is the reading on voltmeter 1?

Don't include units in your answer. Give your answer to 2 significant figures.

• 1.5

• 1.50

• 1.5v

Multiple Choice

In the circuit shown, voltmeter 1 reads 3.0 V and voltmeters 2 and 3 both read 1.5 V. If both lamps break, what will be the new reading on voltmeter 3?

• 6.0 V

• 0.0 V

• 3.0 V

Multiple Choice

When you double the number of cells connected in the same direction and in series, the voltage also doubles. What will be the reading on the voltmeter if the second cell is added?

Don't include units in your answer. Give you answer to two significant figures.

• 3

• 3.0

• 3v

• 3.0 V

Multiple Choice

If lamp 1 breaks, what will the new reading on ammeter 4 be?

• 0.0 A

• 1.0 A

• 2.0 A

Multiple Choice

In the circuit shown, all three ammeters read 0.3 A. If both lamps break, what will the new reading on ammeter 3 be?

• 0.0 A

• 0.3 A

• 0.6 A

Multiple Choice

What kind of circuit is this?

• Series
• Consecutive
• Parallel
• Training

Multiple Choice

What kind of circuit is this?

• Series
• Consecutive
• Parallel
• Training

Multiple Choice

What is the unit of power?

• Amps
• Watts
• Volts
• Joules

Multiple Choice

What is the unit of Current?

• Amps
• Watts
• Volts
• Joules

Multiple Choice

What is the unit of voltage?

• Amps
• Watts
• Volts
• Joules

Multiple Choice

What is the unit of energy?

• Amps
• Watts
• Volts
• Joules

Multiple Choice

If the voltage across the battery was 10V in this diagram. What would the voltage across each bulb be?

• 10V
• 5V
• 20V
• 0V

Multiple Choice

If the current through the battery was 10A in this diagram. What would the current through each bulb be?

• 10A
• 5A
• 20A
• 0A

Multiple Choice

If the current through the battery was 10A in this diagram. What would the current through each bulb be?

• 10A
• 5A
• 20A
• 0A

Multiple Choice

What does the voltage on a battery mean?

• The speed of electron flow through it.
• How tough it is for electrons to flow through it.
• The amount of energy given to the electrons.
• The amount of energy taken away from the electrons.

Multiple Choice

What does the current in a wire tell you?

• The speed of electron flow through it.
• How tough it is for electrons to flow through it.
• The amount of energy given to the electrons.
• The amount of energy taken away from the electrons.

Multiple Choice

What does the resistance of a wire tell you?

• The speed of electron flow through it.
• How tough it is for electrons to flow through it.
• The amount of energy given to the electrons.
• The amount of energy taken away from the electrons.

Multiple Choice

What does the voltage across a bulb tell you?

• The speed of electron flow through it.
• How tough it is for electrons to flow through it.
• The amount of energy given to the electrons.
• The amount of energy taken away from the electrons.

Multiple Choice

What 'flows' in a wire?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

What particle has a negative charge?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

What particle has a positive charge?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

What particle has a no charge?

• Protons
• Neutrons
• Atoms
• Electrons

Multiple Choice

If you increase the resistance of a circuit, what happens?

• Current decreases
• Current increases
• Electrons disappear
• Bulbs get brighter

Multiple Choice

If you decreases the resistance of a circuit, what happens?

• Current decreases
• Current increases
• Electrons disappear
• Bulbs get brighter

Multiple Choice

If you increase the voltage of a circuit, what happens?

• Current decreases
• Current increases
• Electrons disappear
• Bulbs get dimmer

Multiple Choice

If you decrease the voltage of a circuit, what happens?

• Current decreases
• Current increases
• Electrons disappear
• Bulbs get brighter

Multiple Choice

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.

Multiple Choice

What kind of circuit is this?

• series
• parallel

Multiple Choice

wood is a _____?

• conductor
• insulator

Multiple Choice

brass is a _____?

• insulator
• conductor

Multiple Choice

A material in which electrons are able to move easily

• Circuit
• Insulator 
• Resistance 
• Conductor 

Multiple Choice

A material in which electrons are not able to move easily 

• Circuit 
• Insulator 
• Resistance 
• Conductor

Multiple Choice

This circuit has more than one loop. When one light goes out, the others stay on. 

• closed circuit
• series circuit
• parallel circuit
• open circuit

Multiple Choice

Which statement is true?

• The light bulb will light up because the  circuit is complete.
• The light bulb will light up because the  circuit is broken.
• The light bulb will not light up because the  circuit is complete.
• The light bulb will not light up because the  circuit is broken.

Multiple Choice

Electric current is the flow of:

• electrons
• protons
• neutrons
• none of these

Multiple Choice

What type of circuit is pictured?

• A. alternating
• B. overloaded
• C. parallel
• D. series

Multiple Choice

What type of circuit is pictured?

• A. alternating
• B.overloaded
• C.parallel
• D. series

Multiple Choice

what kind of circuit is this?

• parallel
• series
• chris barton
• open

Multiple Choice

this is the symbol for a _____?

• switch
• light 
• battery
• wires

Multiple Choice

what is this symbol for?

• light bulb
• switch
• battery
• resistor