Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

physics > P2 Ai > Flashcards

P2 Ai Flashcards

1
Q

What is the purpose of understanding circuit diagrams?

A

To be able to understand and draw them using the correct symbols.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What symbol represents an open switch in a circuit diagram?

A

Switch open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the symbol for a battery in circuit diagrams?

A

Battery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the components in a circuit?

A

Parts like bulbs, resistors, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the potential difference in an electrical circuit represent?

A

The ‘driving force’ that pushes charge around the circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the unit of electric current?

A

Amperes, A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the unit of electrical charge?

A

Coulombs, C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is required for electrical charge to flow in a circuit?

A

A complete (closed) circuit and a potential difference.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is resistance in the context of electric circuits?

A

Anything that slows down the flow of charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In a single, closed loop circuit, how does the current behave?

A

The current is the same everywhere in the circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the relationship between charge flow, current, and time?

A

Charge flow (C) = Current (A) x Time (s) or Q = It.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the formula for Ohm’s Law?

A

V = IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is sometimes referred to as ‘voltage’?

A

Potential difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If a battery charger passes a current of 2 A for 300 seconds, how much charge is transferred?

A

600 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

True or False: A closed circuit allows electrical charge to flow.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Fill in the blank: Electrical current is a flow of _______.

A

electrical charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the symbol for a filament lamp in circuit diagrams?

A

Filament lamp (or bulb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the symbol for a diode in circuit diagrams?

A

Diode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the symbol for an LED in circuit diagrams?

A

LED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What should you ensure about the wires in a circuit diagram?

A

All wires should be straight lines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the significance of a closed circuit?

A

Allows continuous flow of current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the formula that links potential difference, current, and resistance?

A

V = IR

V is potential difference in volts (V), I is current in amps (A), and R is resistance in ohms (Ω)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does resistance measure?

A

How much the current is slowed down

Greater resistance results in smaller current for a given potential difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens to current if the resistance across a component increases?

A

The current decreases

This is true for a given potential difference across the component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Fill in the blank: The formula linking potential difference (pd) and current is: V = _____

A

IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the current through a 4.0 Ω resistor with a potential difference of 6.0 V across it?

A

1.5 A

Calculated using the formula I = V ÷ R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are ohmic conductors?

A

Components with a fixed resistance

Their resistance does not change with current as long as the temperature remains constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What happens to the current in an ohmic conductor if the potential difference doubles?

A

The current also doubles

Current is directly proportional to potential difference in ohmic conductors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What happens to the resistance of a filament lamp as the current increases?

A

Resistance increases with temperature

The filament heats up and glows brighter as current increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How does a diode behave regarding current flow?

A

Allows current to flow in one direction only

It has very high resistance in the opposite direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

True or False: The resistance of some components remains constant regardless of the current.

A

False

Components like filament lamps and diodes have changing resistance with current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the potential difference across an appliance if the resistance is 46 Ω and the current is 5.0 A?

A

230 V

Calculated using the formula V = IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What factors can affect the resistance of a circuit?

A

The resistance of a circuit can depend on:
* If components are in series or parallel
* The length of wire used in the circuit

For more information on series and parallel components, see p.185.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What equipment is needed to investigate the effect of wire length on resistance?

A

You will need:
* Switch
* Battery
* Ammeter
* Metre ruler
* Crocodile clips
* Thin test wire

These components are typically used in simple circuit experiments.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How can you measure the resistance of a wire in an experiment?

A

Measure the current and potential difference (pd) across the wire using:
* A crocodile clip at 0 cm
* A second crocodile clip at a short distance
* Record the length, current, and pd
* Calculate resistance using R = V ÷ I

This formula is derived from Ohm’s Law (V = IR).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What does a graph of resistance against wire length show?

A

The graph should:
* Have a straight line through the origin
* Show that resistance is directly proportional to length

This indicates that the longer the wire, the greater the resistance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

True or False: Opening the switch between readings can help reduce error in measurements.

A

True

This allows the circuit to cool down, minimizing potential errors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Fill in the blank: The longer the wire, the _______.

A

greater the resistance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the equation used to calculate resistance in a circuit?

A

R = V ÷ I

This equation is based on Ohm’s Law.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the role of a variable resistor in the circuit diagram for investigating resistance?

A

It represents the test wire used in the investigation

Variable resistors allow for adjustments in resistance during experiments.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the first step in measuring the resistance of a wire in the experiment?

A

Attach a crocodile clip to the wire level with 0 cm on the ruler.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How should you plot your results after measuring resistance against wire length?

A

Plot a graph of resistance against wire length and draw a line of best fit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What happens to the current when the wire length increases?

A

The current decreases as resistance increases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What does the I-V characteristic show?

A

How current (I) changes with potential difference (V) across a component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are linear components in I-V characteristics?

A

Components with straight line characteristics, such as a fixed resistor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

How is resistance (R) calculated from I-V characteristics?

A

R = V ÷ I (from V = IR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What types of components should be investigated for I-V characteristics?

A
  • Filament lamp
  • Diode
  • Resistor at a fixed temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What type of current is used in the I-V characteristic experiments?

A

Direct current (dc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the purpose of the variable resistor in the experiment?

A

To change the current in the circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What measurements are taken during the I-V characteristic experiment?

A
  • Current through the component
  • Potential difference across the component
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What happens when the wires connected to the battery are swapped?

A

The ammeter displays negative readings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is plotted on the graph in I-V characteristic experiments?

A

Current on the y-axis and potential difference on the x-axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the shape of the I-V characteristic for a fixed resistor?

A

A straight line, indicating current is directly proportional to potential difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What happens to the resistance of a filament lamp as current increases?

A

Resistance increases, making it harder for current to flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the I-V characteristic of a diode?

A

Current only flows in one direction with very high resistance in the reverse direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

True or False: The filament lamp I-V characteristic shows that current is directly proportional to potential difference.

A

False (it shows that resistance increases with temperature, making it non-linear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Fill in the blank: The resistance of a filament lamp ______ increases as the current increases.

A

resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What should be done with the graphs of I-V characteristics?

A

Draw out those graphs until you’re sketching them in your sleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What does LDR stand for?

A

Light Dependent Resistor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How does the resistance of an LDR change with light intensity?

A

The resistance decreases in bright light and increases in darkness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What are some common uses of LDRs?

A

Automatic night lights, outdoor lighting, burglar detectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is a thermistor?

A

A temperature dependent resistor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How does the resistance of a thermistor change with temperature?

A

Resistance drops in hot conditions and increases in cool conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Where are thermistors commonly used?

A

Car engines, central heating thermostats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is the role of thermostats in relation to thermistors?

A

They turn the heating on when it’s cool and off when it’s warm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is a sensing circuit?

A

A circuit that automatically changes the potential difference across components based on environmental changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

How does a sensing circuit control a fan in a room?

A

The potential difference across the fan increases as the room gets hotter due to the thermistor’s resistance decreasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What happens to the potential difference across a fixed resistor in a sensing circuit as the room heats up?

A

The potential difference across the fixed resistor rises

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

True or False: In a series circuit, if you remove one component, all components stop working.

70
Q

What is the relationship between total resistance in a series circuit and the individual resistances?

A

Total resistance is the sum of individual resistances

71
Q

What happens to the potential difference in a series circuit when additional components are added?

A

The potential difference is shared among the components

72
Q

Fill in the blank: The bigger a component’s resistance, the _______ of the potential difference it takes.

73
Q

How does the arrangement of LDRs and thermistors affect circuit behavior?

A

They can be used to create circuits that respond to changes in light and temperature

74
Q

What is the effect on a fan if it is connected across a thermistor in a circuit as the room gets hotter?

A

The fan would slow down

75
Q

What is the definition of potential difference?

A

The difference in electric potential energy per unit charge between two points

76
Q

What is the configuration of components in a series circuit?

A

All components are connected in a line between the ends of the power supply.

77
Q

What happens when one component is removed in a series circuit?

A

The circuit is broken and all components stop working.

78
Q

In series circuits, how is the total potential difference (pd) of the supply distributed?

A

The total pd is shared between all of the components.

79
Q

How do you calculate the total resistance in a series circuit?

A

By adding the resistances of the individual components.

80
Q

Fill in the blank: In series circuits, the same ______ flows through all components.

81
Q

True or False: In series circuits, the potential difference across each component is equal.

82
Q

What effect does adding a resistor in series have on the total resistance of the circuit?

A

It increases the total resistance.

83
Q

What is the relationship between a component’s resistance and its share of the total pd in a series circuit?

A

The bigger a component’s resistance, the bigger its share of the total pd.

84
Q

If cells are connected in series, what happens to their potential differences?

A

Their potential differences add together to make the total pd across the circuit.

85
Q

Calculate the total resistance for resistors of 2Ω and 3Ω connected in series.

86
Q

What is the formula to calculate current in a circuit?

A

I = V ÷ R

87
Q

In a circuit with a 20V supply and a total resistance of 5Ω, what is the current?

88
Q

Describe the effect of adding resistors in series on the current through each resistor.

A

The current through each resistor is lower because they share the total pd.

89
Q

What is the potential difference of a battery connected in series with a 4Ω, 5Ω, and 6Ω resistor when a current of 0.6A flows through the circuit?

A

Calculate using V = IR: V = 0.6 * (4 + 5 + 6) = 0.6 * 15 = 9V

90
Q

What is the main characteristic of components in parallel circuits?

A

Every component is connected separately to the ends of the power supply.

91
Q

True or False: In parallel circuits, if one loop is removed, other loops are affected.

92
Q

What happens to the potential difference across components in parallel circuits?

A

The potential difference is the same across all components.

93
Q

What is the relationship between the total current and the currents through individual components in parallel circuits?

A

The total current is equal to the sum of all the currents through the separate components.

94
Q

Fill in the blank: At junctions in a parallel circuit, the total current going into a junction must equal the total current _______.

A

leaving it.

95
Q

What is the effect of adding a resistor in parallel on the total resistance?

A

The total resistance is less than the resistance of the smallest of the two resistors.

96
Q

How does adding another loop in a parallel circuit affect current flow?

A

More current can flow around the circuit, increasing the total current.

97
Q

What is the formula that relates resistance, voltage, and current?

98
Q

In a parallel circuit with identical resistors, what can be said about their brightness?

A

All bulbs will be at the same brightness.

99
Q

What is the total current if the current into a junction is 2 A and out is 1 A + A?

100
Q

What happens to the total current and resistance when one resistor is removed from a parallel circuit containing three resistors?

A

The total current decreases and the total resistance increases.

101
Q

What is the first step in setting up a basic circuit?

A

Find at least four identical resistors.

102
Q

What does ‘pd’ stand for in the context of a circuit?

A

Potential difference

103
Q

How do you calculate the resistance of the circuit?

A

R = V ÷ I

104
Q

In a series circuit, what happens to the total resistance when additional resistors are added?

105
Q

In a parallel circuit, what happens to the overall resistance when additional resistors are added?

106
Q

What remains constant when adding resistors in parallel?

A

The pd is the same as before.

107
Q

Fill in the blank: Adding resistors in ______ increases the total resistance of the circuit.

108
Q

Fill in the blank: The more resistors you add in ______, the smaller the overall resistance becomes.

109
Q

What should you plot on the graph to compare results?

A

Number of resistors in the circuit against the total resistance

110
Q

True or False: The total current through the circuit is measured after adding resistors in series.

111
Q

What equipment is recommended to use for a fair test when investigating circuits?

A

The same equipment

112
Q

What type of graph is expected when plotting the total resistance against the number of resistors in parallel?

A

A downward sloping graph

113
Q

What type of graph is expected when plotting the total resistance against the number of resistors in series?

A

An upward sloping graph

114
Q

What is the significance of measuring current in the circuit?

A

It allows for the calculation of resistance.

115
Q

What is the purpose of the practical experiment described?

A

To practice building circuits from diagrams.

116
Q

What is an alternating potential difference?

A

A potential difference that is constantly changing direction.

Alternating current (AC) is produced by this type of potential difference.

117
Q

What is the UK mains supply voltage?

A

Around 230 V.

This is the electricity supply in homes.

118
Q

What is the frequency of the AC mains supply in the UK?

A

50 Hz.

Hertz (Hz) is the unit of frequency.

119
Q

What is direct current (DC)?

A

A current that is always flowing in the same direction.

It is created by a direct potential difference.

120
Q

What type of current do cells and batteries supply?

A

Direct current (DC).

121
Q

What are the three wires in a typical three-core electrical cable?

A
  • Live wire (brown)
  • Neutral wire (blue)
  • Earth wire (green and yellow)

These wires are covered with plastic insulation.

122
Q

What is the function of the live wire?

A

Provides the alternating potential difference from the mains supply.

It is at about 230 V.

123
Q

What is the function of the neutral wire?

A

Completes the circuit.

When the appliance is operating normally, current flows through the live and neutral wires. It is around 0 V.

124
Q

What is the function of the earth wire?

A

Acts as a safety wire to prevent electric shocks.

It is connected to the metal casing of an appliance and helps to divert current in case of a fault.

125
Q

What happens if the live wire touches the casing of an appliance?

A

Current flows away through the earth wire.

This helps to prevent electric shock.

126
Q

What is the potential difference of the earth wire?

A

Around 0 V.

127
Q

What can touching the live wire cause?

A

A dangerous electric shock.

This can happen even if the switch is turned off.

128
Q

True or False: The potential difference between the live wire and your body is 0 V.

A

False.

Your body is at 0 V, while the live wire has a potential difference of 230 V.

129
Q

What risks are associated with any connection between live and earth wires?

A

It could cause a huge current to flow, resulting in a fire.

130
Q

Fill in the blank: The ______ wire is at about 230 V.

131
Q

Fill in the blank: The ______ wire is around 0 V.

132
Q

Fill in the blank: The ______ wire prevents the appliance from becoming live.

133
Q

What happens whenever work is done in terms of energy?

A

Energy is transferred.

134
Q

What is done when a charge moves around a circuit?

A

Work is done against the resistance of the circuit.

135
Q

How is energy transferred when work is done by a charge?

A

Energy is transferred electrically.

136
Q

What do electrical appliances transfer to components in the circuit?

137
Q

How do kettles transfer energy?

A

Electrically from the mains supply to the thermal energy store of the heating element.

138
Q

How is energy transferred from a battery to a handheld fan?

A

From the battery to the kinetic energy store of the fan’s motor.

139
Q

What is the relationship between power and energy transferred by an appliance?

A

The total energy transferred depends on how long the appliance is on for and its power.

140
Q

Define power in the context of electrical appliances.

A

The energy that it transfers per second.

141
Q

What is the equation for energy transferred by electrical work?

A

Energy transferred (J) = Power (W) X Time (s)
E = Pt

142
Q

If a 600 W microwave is used for 5 minutes, how much energy does it transfer?

A

180,000 J.

143
Q

How do you convert 5 minutes into seconds?

A

t = 5 × 60 = 300 s.

144
Q

What does the power rating of an appliance indicate?

A

How much energy is transferred between stores when the appliance is used.

145
Q

True or False: An appliance with a higher power rating will cost less to run for a given time.

146
Q

How much energy does a 250 W TV transfer in 2 hours?

A

Calculate the energy using E = Pt with t = 7200 s.

147
Q

How much energy does a 375 W TV transfer in 2 hours?

A

Calculate the energy using E = Pt with t = 7200 s.

148
Q

Calculate the power if an appliance transfers 6000 J of energy in 30 seconds.

A

Power = E / t = 6000 J / 30 s.

149
Q

What is the significance of an appliance’s power rating?

A

It indicates the rate at which energy is transferred.

150
Q

What is the formula for calculating energy transferred?

A

E = QV

Where E is energy transferred, Q is charge flow, and V is potential difference.

151
Q

In the example of an electric toothbrush, how much energy is transferred with a 3.0 V battery and 140 C of charge?

A

420 J

Calculated using E = QV = 140 × 3.0.

152
Q

What is the formula for calculating power in terms of potential difference and current?

A

P = VI

Where P is power, V is potential difference, and I is current.

153
Q

How can power be calculated if the potential difference is not known?

A

P = I²R

Where R is resistance.

154
Q

If a motor has a power of 1250 W and a resistance of 50 Ω, what is the current flowing through it?

A

25 A

Calculated using P = I²R, rearranged to I = √(P/R).

155
Q

What is the current flowing through an appliance connected to a 12 V source with a current of 4.0 A?

A

4.0 A

This is given directly in the problem.

156
Q

If an appliance has a power of 2300 W and a current of 10.0 A, what is the resistance of the appliance?

A

230 Ω

Calculated using P = I²R, rearranged to R = P/I².

157
Q

True or False: The power of an appliance is the energy transferred in a given time.

A

True

Power is defined as energy transferred per unit time.

158
Q

Fill in the blank: Power also depends on current and _______.

A

Potential Difference

Power is calculated using both current and potential difference.

159
Q

What is the unit of power?

A

Watt (W)

Power is measured in watts.

160
Q

What does the symbol ‘R’ represent in the power equations?

A

Resistance

Resistance is measured in ohms (Ω).

161
Q

What is the relationship between energy transferred, charge, and potential difference?

A

Energy transferred is proportional to the product of charge and potential difference

E = QV shows this relationship.

162
Q

What is the national grid?

A

A giant system of cables and transformers that covers the UK

It transfers electrical power from power stations to consumers.

163
Q

What does the national grid do?

A

Transfers electrical power from power stations to consumers across the UK

Consumers refer to anyone who is using electricity.

164
Q

What must electricity production do to meet demand?

A

Produce enough electricity for everyone to have it when they need it

The amount of electricity used changes throughout the day.

165
Q

How do power stations manage fluctuations in electricity demand?

A

They often run at well below their maximum power output

This allows them to increase power if needed.

166
Q

What is the formula for calculating power in the context of electricity?

A

P = VI

Where P is power, V is potential difference, and I is current.

167
Q

Why does the national grid use a high potential difference?

A

To reduce energy lost as thermal energy stores

A high current causes more energy loss due to heating of wires.

168
Q

What type of transformers are used to increase potential difference in the national grid?

A

Step-up transformers

They increase the potential difference from power stations to electric cables.

169
Q

What type of transformers are used to decrease potential difference before electricity reaches homes?

A

Step-down transformers

They bring the potential difference back down to safe levels.

170
Q

True or False: The national grid transfers electricity at a low potential difference to minimize energy loss.

A

False

The national grid transmits electricity at a very high potential difference.

171
Q

Fill in the blank: The national grid can cope with high demand even if another station shuts down without _______.

physics (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions