Physics Paper 1 Flashcards
1
Q
Kinetic Energy
A
Energy associated with the motion of an object.
2
Q
Thermal Energy
A
Energy related to the temperature of an object.
3
Q
Chemical Energy
A
Energy stored in the bonds of chemical compounds.
4
Q
Gravitational Potential Energy
A
Energy stored in an object as it is raised above the ground.
5
Q
Elastic Potential Energy
A
Energy stored in elastic materials as the result of their stretching or compressing.
6
Q
Electrostatic Energy
A
Energy stored in electric charges.
7
Q
Magnetic Energy
A
Energy stored in magnetic fields.
8
Q
Nuclear Energy
A
Energy stored in the nucleus of an atom.
9
Q
Energy Transfer Mechanisms
A
Ways in which energy is transferred: mechanically, electrically, by heating, and by radiation.
10
Q
Kinetic Energy Equation
A
Ek = 1/2mv^2
11
Q
Elastic Potential Energy Equation
A
Ee = 1/2ke^2
12
Q
Gravitational Potential Energy Equation
A
Ep = mgh
13
Q
Energy Units
A
Energy is measured in joules (J).
14
Q
Mass Units
A
Mass is measured in kilograms (kg).
15
Q
Velocity Units
A
Velocity is measured in meters per second (m/s).
16
Q
Force Units
A
Force is measured in newtons per meter (N/m).
17
Q
Extension Units
A
Extension is measured in meters (m).
18
Q
Gravitational Field Strength Units
A
Gravitational field strength is measured in newtons per kilogram (N/kg).
19
Q
Height Units
A
Height is measured in meters (m).
20
Q
Thermal Energy Change Equation
A
∆E = mc∆θ
21
Q
Specific Heat Capacity
A
Energy needed to raise 1 kg of a substance by 1°C, measured in joules per kilogram per degree Celsius (J/kg°C).
22
Q
Power Equation
A
Power = energy transferred ÷ time (P = E/t)
23
Q
Conservation of Energy
A
Energy cannot be created or destroyed, only transformed.
24
Q
Energy Dissipation
A
Some energy becomes spread out to surroundings and is considered wasted.
25
Lubrication
A method to reduce energy losses by reducing friction.
26
Thermal Insulation
A method to reduce energy losses by minimizing heat transfer.
27
Efficiency
The energy efficiency for any energy transfer can be calculated using the equation: E c c =
28
Efficiency Calculation
Efficiency may also be calculated using the equation: c c =
29
Efficiency Expression
Efficiency is expressed as a Percentage or Decimal
30
Increase Efficiency
Reduce waste, improve design
31
Non-renewable Energy Resources
coal, oil, gas, nuclear
32
Renewable Energy Resources
wind, solar, geothermal, hydroelectric, wave, tidal, bio-fuels
33
Renewable Energy Definition
Renewable = replenished naturally
34
Energy Resource Reliability
Some energy sources are more reliable than others
35
Environmental Impacts of Energy
emissions, habitat damage, resource use
36
Uses of Energy
Transport, Electricity generation, Heating
37
Current
flow of electric charge (measured in amperes, A)
38
Potential Difference (Voltage)
pushes charge through a circuit (measured in volts, V)
39
Resistance
opposes flow of current (measured in ohms, Ω)
40
Charge Flow Equation
Q=I×t
41
Potential Difference Equation
V=IR
42
Required Practical 3
Set up a circuit with a power supply, ammeter, voltmeter, and a length of wire on a ruler.
43
Resistance Calculation
Calculate resistance using =
44
Ohmic Conductors
Constant resistance (e.g. wire at constant temp)
45
Filament Lamp
Resistance increases as it heats up
46
Diode
Current only flows in one direction
47
Thermistor
Resistance decreases as temperature increases
48
LDR (Light-Dependent Resistor)
Resistance decreases with light intensity
49
I-V Characteristics Investigation
Investigate I-V characteristics of resistor, lamp & diode
50
Required Practical 4
Set up a circuit with a power supply, ammeter, voltmeter, and the component being tested (e.g. resistor, filament lamp, diode).
51
Series Circuits
Same current throughout; Voltage shared between components; Total resistance = R₁ + R₂.
52
Parallel Circuits
Same voltage across each branch; Total current = sum of branch currents; Total resistance < smallest individual resistor.
53
AC vs DC
UK mains: AC at 50 Hz, 230 V; Batteries: DC.
54
3-Core Cables
Live = Brown (230 V); Neutral = Blue (0 V); Earth = Green/Yellow (safety).
55
Live Wire Safety
Live wire is dangerous even when switch is off; Never connect live wire to earth!
56
Power Equation
Power = potential difference × current; P=V×I.
57
Power Equation (Resistance)
Power = current² × resistance; P=I^2×R.
58
Energy Transferred Equation (Power)
Energy transferred = power × time; E=P×T.
59
Energy Transferred Equation (Charge)
Energy transferred = charge × potential difference; E=Q×V.
60
National Grid
Transfers electricity from power stations to homes; Uses step-up transformers to reduce energy loss during transmission; Step-down transformers reduce voltage for safe domestic use.
61
Static Charge
Rubbing insulators causes electrons to transfer; Like charges repel; opposite charges attract.
62
Electric Fields
Charged objects create fields; Stronger when closer; Explain non-contact forces and sparks.
63
Density Equation
Density (ρ) = Mass (m) / Volume (V); Units: ρ = kg/m³; m = kg; V = m³.
64
Density of Regular Objects Method
Measure dimensions using a ruler; Calculate volume; Measure mass with a balance; Calculate density.
65
Density of Irregular Objects Method
Submerge object in a displacement can or measuring cylinder; Record volume of displaced water; Measure mass; Calculate density as above.
66
Change of State
Diagrams can model solids, liquids, gases; Mass is conserved during changes of state.
67
Physical changes
Changes that do not alter the chemical composition of a substance.
68
Mass stays the same
The total mass of a system remains constant during physical changes.
69
Reversible
Physical changes can return to their original properties.
70
Internal Energy
Total kinetic + potential energy of all particles in a system.
71
Heating increases internal energy
Heating can raise temperature or cause a change of state.
72
Temperature Change Equation
ΔE = m × c × Δθ.
73
ΔE
Change in thermal energy (J).
74
m
Mass (kg).
75
c
Specific heat capacity (J/kg°C).
76
Δθ
Temperature change (°C).
77
Specific heat capacity
Energy needed to raise 1 kg by 1°C.
78
Specific Latent Heat Equation
E = m × L.
79
E
Energy (J).
80
L
Specific latent heat (J/kg).
81
Types of Latent Heat
Fusion: solid ↔ liquid; Vaporisation: liquid ↔ gas.
82
Heating/cooling graphs
Flat lines = changes of state; Sloped lines = temperature change.
83
Particle Motion in Gases
Gas particles exhibit constant, random motion.
84
Temperature ∝ average kinetic energy
Temperature is directly proportional to the average kinetic energy of gas particles.
85
Increase temp → increase pressure
Increasing temperature leads to increased pressure if volume is fixed.
86
Pressure in Gases Equation
p × V = constant.
87
p
Pressure (Pa).
88
V
Volume (m³).
89
Increase volume = lower pressure
Increasing the volume of a gas decreases its pressure at constant temperature.
90
Decrease volume = higher pressure
Decreasing the volume of a gas increases its pressure at constant temperature.
91
Doing Work on a Gas
Work transfers energy which increases internal energy and can raise the temperature of the gas.
92
Atoms
Atoms have a radius of approximately 1 × 10⁻¹⁰ m.
93
Nucleus
Contains protons and neutrons, with most mass concentrated in it.
94
Atomic number
Number of protons in an atom.
95
Mass number
Total number of protons and neutrons in an atom.
96
Isotopes
Same element with different numbers of neutrons.
97
Radioactive Decay
Some unstable nuclei emit radiation randomly.
98
Activity
Number of decays per second (Becquerels, Bq).
99
Count-rate
Number of decays detected per second.
100
Radiation types
Alpha (α) = 2 protons + 2 neutrons; Beta (β) = electron from neutron splitting; Gamma (γ) = electromagnetic wave.
101
Half-life
Time for count rate/number of nuclei to halve.
102
Radioactive Contamination
Presence of radioactive particles on/in materials.
103
Irradiation
Exposure to radiation without becoming radioactive.
104
Background Radiation
Constant low-level radiation from natural and man-made sources.
105
Radiation dose
Measured in sieverts (Sv), indicating potential biological harm.
106
Nuclear Fission
Splitting of large, unstable nuclei, releasing energy.
107
Nuclear Fusion
Joining of two light nuclei to form a heavier nucleus, occurring in stars.
