Physics Paper 1 Flashcards
1
Q
What is gravitational potential energy store?
A
Energy an object has because it is above the Earth’s Surface
2
Q
What is the formula for gravitational potential energy?
A
Ep = m g h (g . p . e = mass x gravitational field strength x height)
3
Q
What is a kinetic energy store?
A
Energy an object has because it is moving
4
Q
What is the formula for kinetic energy?
A
Ek = 1/2 m v 2 (kinetic energy = 0.5 x mass x (speed)2
5
Q
What is chemical energy store?
A
Energy stored in chemical bonds, such as between molecules: food, fuel and batteries
6
Q
What is an elastic potential energy store?
A
The energy stored when an object is stretched or compressed.
7
Q
What is internal (thermal) energy store?
A
Energy stored by an object because of it is warm: the total kinetic and potential energy of the particles in an object
8
Q
What is specific heat capacity?
A
The amount of energy needed to raise the temperature of 1kg of a substance by 1℃
9
Q
What is the law of conservation of energy?
A
Energy cannot be created or destroyed, it can only be transferred, stored or dissipated
10
Q
What is a system?
A
An object or group of objects
11
Q
What is a closed system?
A
A system which energy cannot leave or enter
12
Q
What is dissipation?
A
When energy spreads out into less useful stores, usually increasing the thermal store of the surroundings
13
Q
What is power?
A
Rate of energy transfer
Rate of work done
14
Q
What is the formula that links power, energy transferred and time
A
P = E/t (Power = energy transferred/time)
15
Q
What is the formula that links power, work done and time
A
P = W/t (Power = work done/time)
16
Q
What is the unit for energy?
A
J (joules)
17
Q
What is the unit for power?
A
W (watts)
18
Q
What two factors affect the rate of thermal energy transfers?
A
Thermal conductivity of the material, thickness of material
19
Q
Give two ways of reducing unwanted energy transfers
A
Thermal insulation of heated buildings; lubrication of moving parts
20
Q
What are the two formulas for efficiency?
A
efficiency = useful output energy transfer / total input energy transfer
efficiency = useful power output / total power input
21
Q
(HT) Desribe two ways of increasing efficiency
A
Reduce unwanted energy transfers e.g. bu lubricating moving parts or insulating to reduce unwanted heat transfers
22
Q
What is a renewable energy resource?
A
A renewable energy resource is one that is being (or can be) replenished as it is used.
23
Q
Name the 4 non-renewable energy resources.
A
The fossil fuels: coal, oil and gas
Nuclear
24
Q
Name 4 renewable energy resources
A
Solar, wind, hydroelectric, biofuels
25
State the advantages of using fossil fuels
Helps meet current demand
Reliable
Cheap to extract and use
26
State the disadvantages of using fossil fuels
Produces greenhouse gases
Causes pollution
Oil spills
27
State the advantages of using nuclear energy
Does not produce greenhouse gases or pollute the atmosphere
Reliable
28
State the disadvantages of using nuclear energy
Produces radioactive waste
Expsensive to build and run power stations
29
State the advantages of using biofuels
The CO2 released when burning the fuel is balanced by CO2 absorbed by the plant when growing it
30
State the disadvantages of using biofuels
Consumes resources and land that could be used to produce food
31
State the advantages of using wind energy
Does not produce greenhouse gases or pollute the atmosphere
Land can still be used for farming
32
State the disadvantages of using wind energy
Unreliable
Noise pollution
Visual pollution
33
State the advantages of using solar energy
Does not produce greenhouse gases or pollute the atmosphere
Good for producing energy in remote locations
34
State the disadvantages of using solar energy
Not reliable
Solar farms can use up farm land
35
What is current?
The rate of flow of electrical charge
36
What is needed for current to flow?
A potential difference and a closed circuit
37
What formula links current, charge and time?
Q = It (Charge = current x time)
38
What is the unit of charge?
C (Coulombs)
39
What is the unit of current?
A (Amps)
40
What is resistance?
The opposition to the flow of current
41
What is the unit of resistance?
Ω (Ohms)
42
What is the unit of potential difference?
V (Volts)
43
What formula links potential difference, curent and resistance?
V = IR (potential difference = current x resistance)
44
How do we measure current?
With an ammeter in series
45
How can we measure potential difference?
With a voltmeter in parallel
46
How do we find the resistance of a component or circuit?
Find the current and potential difference, then use the formula V = IR
47
What is this component?
Open switch
48
What is this component?
Closed switch
49
What is this component?
Cell
50
What is this component?
Battery
51
What is this component?
Diode
52
What is this component?
Resistor
53
What is this component?
Variable resistor
54
What is this component?
LED
55
What is this component?
lamp
56
What is this component?
fuse
57
What is this component?
voltmeter
58
What is this component?
ammeter
59
What is this component?
thermistor
60
What is this component?
LDR
61
What is the difference between series and parallel?
Components in series are on the same loop of the circuit; components in parallel are in separate loops
62
What happens to the current in series?
Stays the same
63
What happens to current in parallel?
Splits up then recombines
64
What happens to the potential difference in series?
Total p.d. is split across the components
65
What happens to potential differences in parallel?
Stays the same
66
What happens to resistance in series?
Total resistance is the sum of the resistances of all the components
67
What happens to resistance in parallel?
Total resistance is lower than the resistance of the component with the smallest resistance
68
What is the difference between direct current (DC) and alternating current (AC)?
In DC, the charges move continuously in one direction. In AC, charges continuously change direction (pd.is continuously changed direction)
69
Describe 3 features of UK mains electricity
230V, AC, 50Hz
70
In a 3-core cable, what are the features of the live wire?
Alternates its potential difference from maximum +325V to -325V 50 times per second
71
In a 3-core cable, what are the features of the neutral wire?
Potential difference = 0V - completes the circuit between the appliance and the local substation
72
In a 3-core cable, what are the features of the earth wire?
Potential difference = 0V - only carries current in the event of a fault
73
Why is the live wire dangerous even when the switch in a mains circuit is open?
Because it is at a very high p.d. compared to earth, so that if a person touched it they would be electrocuted as current flowed through them to earth
74
What formula links power, potential difference and current?
P=VI
Power = potential difference x current
75
What formula links power, current and resistance?
P=I2R
Power = current x current x resistance
76
How is electrical power transferred in the National Grid?
At very high potential difference between power stations and consumers, then stepped down to 230V before use.
77
Why is transferring electrical power at very high potential difference across long distances an efficient method?
Because power lost due to heating is proportional to I2, a higher pd means a lower I and therefore less power lost
78
What is this component?
Diode
79
What is this component?
LDR
80
What is this component?
Thermistor
81
What component does this graph show?
Ohmic conductor
82
What component does this graph show?
Filament Lamp
83
What component does this graph show?
Diode
84
Why does resistance increase in series but decrease in parallel?
Resistors in series must have the total p.d. shared between them, so current through each is lower. Adding more resistors in parallel draws more current as each has the same p.d. across it.
85
What is the formula that links density, mass and volume?
density = mass/volume
86
Explain the differences in density between solids, liquids and gases
Solids have the highest density (in general) because the particles are closely packed and have little space in between them. Gases are the least dense as there is a lot of space between particles.
87
What is the name for the state change from solid to liquid?
Melting
88
What is the name for the state change from liquid to gas?
Evaporating/boiling
89
What is the name for the state change from gas to liquid?
Condensing
90
What is the name for the state change from liquid to solid?
Freezing
91
What is the name for the state change from solid to gas?
Sublimation
92
What happens to mass during a state change?
Remains constant
93
What happens to the energy stores of a system when you heat it?
It increases
94
What two things can happen when you heat a system?
Its temperature can increase or its state can change
95
What is the difference between specific heat capacity and latent heat?
Specific heat capacity describes thermal energy being used to increase temperature (kinetic energy of particles) whereas latent heat describes thermal energy being used to change the state of a substance (increase the potential energy of particles)
96
How does increasing the temperature of a gas at constant volume affect the pressure of the gas?
Pressure will increase
97
Describe the structure of the atom.
Positively charged nucleus surrounded by negatively charged electrons
98
Where is almost all of the mass of the atom?
In the nucleus
99
How does the radius of the nucleus compare to the radius of the atom?
The nucleus is muc muc smaller than the atom
100
What is the nucleus of the atom composed of?
Protons and neutrons
101
What fo all nuclei of atoms of the same element have in common?
Number of protons
102
How can atoms of the same element differ in mass?
By having different numbers of neutrons
103
What was the plum-pudding model of the atom?
An early model of the atom where the atom was a ball of positive charge with negative electrons scattered throughout
104
Why was the plum-pudding model of the atom proposed?
Because electrons had been discovered and were known to be smaller than atoms and to have a negative charge
105
What was the nuclear model of the atom?
The model that was proposed after the plum-pudding model, with atoms having a small positively charged nucleus surrounded by negative electrons
106
Why was the nuclear model of the atom proposed?
Because the alpha-particle scattering experiment produced evidence that could not be explained by the plum-pudding model
107
How are electrons arranged around the atomic nucleus?
Orbit at fixed distances
108
What happens to an atom's electrons when electromagnetic radiation is absorbed or emitted?
Distance from the nucleus may change or outer electrons may be knocked out of the atom
109
What is ionisation?
An atom is turned into an ion (charged particle) by the loss or gain of an electron
110
Name the 3 ways an unstable nucleus may become more stable
By emitting an alpha particle, beta particle, or neutron
111
What is an alpha particle made of?
2 protons and 2 neutrons
112
What is the mass of an alpha particle?
4
113
What is the charge (proton number) of an alpha particle?
2
114
What are the two symbols for alpha particles?
⁴₂He; ⁴₂α
115
What is a beta particle made of?
A fast-moving electron
116
What is the mass of a beta particle?
Very small
117
What is the charge of a beta particle?
-1
118
What are the two symbols for beta particles?
⁰-₁β; ⁰-₁e
119
How is the nucleus affected by the emission of an alpha particle?
Mass decreases by 4, atomic (proton) number decreases by 2
120
How is the nucleus affected by the emission of a beta particle?
Mass stays the same, atomic (proton) number increases by 1
121
How is the nucleus affected by the emission of a gamma wave?
There is no change to mass number or atomic number
122
What are the 2 definitions of half-life?
The time taken for the number of nuclei to halve; the time taken for the activity to reduce by half
123
How is half-life related to the random nature of radioactive decay?
Because radioactive nuclei exist in huge numbers, predictions can be made about overall activity despite individual decays being unpredictable.
124
How do the penetration properties of alpha-particles, beta-particles and gamma waves
compare?
Gamma waves are the most penetrating, beta in the middle, and alpha the least penetrating.
125
What is the difference between contamination and irradiation?
In contamination, a radioactive material is transferred to the object in question.
In irradiation, no radioactive material is transferred: the object experiences radiation from a source separate from it.
126
What are the hazards from contamination?
Risk of ionisation until the radioactive material has been removed/activity has decreased sufficiently
127
What are the hazards from irradiation?
Risk of ionisation while irradiation is happening but no increase risk afterwards
128
What happens to the activity of a radioactive source over time?
It reduces according to its half-life but never get to zero
129
How does the half-life affect the risk from a radioactive source?
The shorter the half-life, the faster the risk will decrease
130
What is a gamma wave?
An electromagnetic wave (no mass or charge) sometimes given out by a nucleus after emitting a particle
131
In atomic notation, what is represented by these symbols?
X= element; Y = atomic mass; Z= atomic number (number of protons)
132
What is the relationship between scientific theory and evidence?
When new evidence is discovered theories change to fit the evidence
