Electric Circuits

Question 1

What is the function of a battery?

Answer 1

To provide power to a circuit

Question 2

What is a cell?

Answer 2

An energy source for a circuit

Question 3

What is a battery?

Answer 3

Multiple cells

Question 4

What is the function of a connecting wire?

Answer 4

To allow electrons to flow

Question 5

What is the function of a switch?

Answer 5

To “pause” and “restart” the flow of charge

Question 6

What is the function of a resistor?

Answer 6

To oppose the flow of charge

Question 7

What is the function of a rheostat?

Answer 7

To allow the resistance to be adjusted

Question 8

What is another name for a rheostat?

Answer 8

Potentiometer

Question 9

What is the function of a lightbulb?

Answer 9

To show current in the form of light

Question 10

What is the function of a LED?

Answer 10

To allow current to flow in one direction

Question 11

What is the function of an ammeter?

Answer 11

To measure current

Question 12

What is the function of a voltmeter?

Answer 12

To measure the potential difference in current

Question 13

What is the difference between emf and potential difference?

Answer 13

Emf is voltage when current is not flowing

Potential difference is voltage when current if flowing

Question 14

How are pd and emf measured?

Answer 14

In Volts

Question 15

How should a voltmeter be connected in a circuit?

Answer 15

In parallel

Question 16

Why does a voltmeter need to be connected in parallel?

Answer 16

It has a high resistance
If it were connected in series, it would serve as another resistor
This would affect the reading

Question 17

What is current?

Answer 17

The number of coulombs of charge that flow past a point in the circuit every second

Question 18

What are the two requirements for charges to be able to flow in a circuit?

Answer 18

There must be no breaks in the circuit

The charges must have energy to be able to move

Question 19

What is the definition of current?

Answer 19

The rate of flow of charge

Question 20

What is the symbol for current?

Answer 20

I

Question 21

What is the measurement of current?

Answer 21

Ampere

Question 22

What is one ampere?

Answer 22

One coulomb that flows past a certain point in one second

Question 23

What is the equation for current?

Answer 23

Current is equal to charge over time
Q
I = —
Δt

Question 24

What is the conventional flow of current?

Answer 24

From the positive terminal of a battery to the negative terminal of a battery

Question 25

How is the direction of current shown?

Answer 25

Using arrowheads

Question 26

What instrument is used to measure current?

Answer 26

An ammeter

Question 27

How is an ammeter connected to a circuit?

Answer 27

In series

Question 28

Why can an ammeter be connected in series?

Answer 28

It has a very low resistance | It does not decrease the current in a circuit

Question 29

What is the definition of resistance?

Answer 29

The property of a material which causes it to oppose the flow of charge through it

Question 30

When can resistance be a detriment?

Answer 30

When current does not need to be opposed

Question 31

Give an example of when resistance is detrimental

Answer 31

High voltage transmission lines If there is too much resistance, they heat up This causes energy to be lost to the environment

Question 32

When can resistance be useful?

Answer 32

When the heat or light energy that resistors cause to be released is needed

Question 33

Give two examples of where resistance is useful

Answer 33

Heating elements | In electronics

Question 34

How can resistance be useful in electronics?

Answer 34

It restricts the flow of current to other components, thereby protecting them

Question 35

How do reinstalls cause things to heat up?

Answer 35

Electrons bump into the particles of the resistor Kinetic energy is transferred Raises the temperature of the resistor

Question 36

What is the formula for resistance?

Answer 36

Resistance is equal to voltage over current V R = --- I

Question 37

What is the relationship between resistance and voltage?

Answer 37

Directly proportional | As the one increases, so does the other

Question 38

What is the relationship between resistance and current?

Answer 38

Inversely proportional | As the one increases, the other decreases

Question 39

What is the unit of measurement for resistance?

Answer 39

The ohm

Question 40

What is the symbol for an ohm?

Answer 40

Ω

Question 41

What is an ohm?

Answer 41

One volt per ampere

Question 42

What four factors affect resistance?

Answer 42

Length Thickness or cross-sectional area Temperature Type of material

Question 43

How does length affect resistance?

Answer 43

The greater the length of a resistor, the more resistance it has

Question 44

How does thickness or cross-sectional area affect resistance?

Answer 44

The greater the cross-sectional area of a resistor, the smaller its resistance

Question 45

How does temperature affect resistance?

Answer 45

The higher the temperature of a resistor, the greater its resistance

Question 46

How does the type of material affect resistance?

Answer 46

The greater the resistivity of a metal, the greater its resistance

Question 47

What does "resistors connected in series" mean?

Answer 47

There is only one path along which the current can flow

Question 48

What does mean to have "resistors connected in parallel"?

Answer 48

There is more than one path along which current can flow

Question 49

How is current affected when resistors are connected in series?

Answer 49

The more resistors there are, the slower the current flows. However, current is equal across all of the resistors

Question 50

What is the formula for finding the equivalent resistance of resistors connected in series?

Answer 50

Rtotal = r1 + r2 …

Question 51

How is voltage affected by resistors connected in series?

Answer 51

It is divided | The amount of voltage in one resistor is proportional to the a,punt of resistance it offers

Question 52

What results in a potential difference across a resistor?

Answer 52

Energy is transferred as it passes through the resistor | The decrease in potential electrical energy results in a potential difference across the resistor

Question 53

What is equivalent resistance in a parallel circuit like?

Answer 53

It is smaller than the resistance of lowest resistor in the set

Question 54

How is equivalent resistance in a parallel circuit calculated?

Answer 54

1 1 1 1 -- = -- + -- + -- … Rp r1 r2 r3

Question 55

How is current affected when resistors are connected in parallel?

Answer 55

It is divided | The sum of the current in the branches is equal to the total current in the circuit

Question 56

How is potential difference affected by resistors in parallel?

Answer 56

It is equal to the potential resistance across the whole combination

Question 57

How do cells work?

Answer 57

They convert chemical potential energy into electrical energy

Question 58

What are the three common components in a cell?

Answer 58

Positive electrode Electrolyte Negative electrode

Question 59

What form is the electrolyte in a cell?

Answer 59

It can be a liquid, paste or a powder

Question 60

What is the electrolyte in an alkaline cell?

Answer 60

Potassium hydroxide

Question 61

What does the negative terminal of an alkaline cell consist of?

Answer 61

Zinc powder

Question 62

What does the positive terminal of an alkaline cell consist of?

Answer 62

Manganese dioxide

Question 63

What happens when this alkaline cell is in use?

Answer 63

The manganese dioxide is converted into manganese oxide and hydroxide ions These ions react with the zinc metal This forms zinc oxide, water and electrons

Question 64

What constitutes an electric current?

Answer 64

Moving charges

Question 65

When is a cell said to be flat?

Answer 65

When too few electrons are being generated

Question 66

What causes a cell to go flat?

Answer 66

The manganese oxide has been almost used up