Triple Higher Physics Paper 1

Current

The flow of electric charge. The greater the rate of flow, the higher the current. It is measured in amps (A),

Charge Equation

Charge (C) = current (A) x time (s)

Resistance

The measure of how it resists the flow of charge. It is measure in ohms and the higher it is, the more difficult it is for charge to flow and the lower the current.

Potential Difference

This tells us the difference in electrical potential from one point to another. It can be thought of as an electrical push and the bigger it is across a component, the greater the flow of charge through the component and the bigger the current. It is measured in Volts.

Potential Difference Equation

Potential Difference (V) = current (A) x resistance (ohms)

Resistance Required Practical

1) set up a standard test circuit.
2) pre-test the circuit and adjust the supply voltage to ensure that there is a measurable difference in readings taken at the lowest and highest temperatures.
3) record the voltage and current at a range of lengths, using crocodile clips to grip the wire at different points.
4) use the variable resistor to keep the current through the wire the same at each length.
5) use the voltage and current measurements to calculate the resistance.

V - I Graph

Shows the relationship between voltage and current and can be used to determine resistance.

V - I Required Practical

1) set up a standard test circuit.
2) use the variable resister to adjust the pd across the rest component.
3) measure the voltage and current for a range of voltage values.
4) repeat the experiment at least 3 times and calculate the mean.
5) repeat for the other components to be tested.

Resistor

An electrical device that resists the flow of electrical current.

Filament Lamps

A light in which the resistance increases when temperature increases.

Diode

A device that allows current to flow in only one direction.

Thermistor

A resistor that changes its resistance when a change of temperature occurs.

Light Dependent Resistor

An electrical component with a resistance that decreases as the light intensity incident on it increases.

Switch

A device that opens or closes a circuit.

Cell

A chemical store of energy that can be transferred by electricity.

Battery

A device that converts chemical energy to electrical energy.

Variable Resistor

A resistor whose resistance can be changed.

Light Emitting Diode

A diode that will produce light when current flows through it.

Lamp / Bulb

Component which changes electrical energy into light energy.

Fuse

A safety device with a thin metal strip that will melt if too much current passes through a circuit.

Voltmeter

A device used to measure pd (voltage)

Ammeter

A device used to measure current.

Series Circuit

A circuit in which all parts are connected end to end to provide a single path of current.
R(total) = R(1) + R(2)...

Parallel Circuit

A circuit that contains more than one path for current flow.

Power

The rate at which work is done.

Power Equation

• Power (W) = pd (V) x current (A)
OR
• Power (W) = (current (A) )squared x resistance (ohms)
OR
• Power (W) = energy transferred (J) / time (s)

Efficiency

The ratio of useful energy out to total energy in.

Efficiency Equation

• Efficiency (%) = (useful energy transfer (J) / (total energy transfer (J) ) x 100
OR
• Efficiency (%) = (useful power output (W) / total power output (W) ) x 100

Direct Current

This has a potential difference that is always positive or always negative and is supplied by cells and batteries.

Alternating Current

This has a potential difference that alternates from positive to negative and is used in mains electricity.

Mains Electricity

This is 230V and changes direction 59 times a second. It uses 3 core cables:
• earth wire (green and yellow stripes) - a safety wire.
• neutral wire (blue) - completes the circuit.
• live wire (brown) - carries alternating potential from the supply.

Energy Transferred Equation

• energy transferred (J) = power (W) x time (s)
OR
• energy transferred (J) = charge flow (A) x pd (V)

The National Grid

A system of cables and transformers linking power stations to homes:
1) power station.
2) step up transformer.
3) transmission cables.
4) step down transformer.
5) houses, etc.

Energy Rule

Energy is never created or destroyed.

Power Station

This transfers the energy supply into electrical energy.

Set Up Transformers

This increases the pd from the power station to the transmission cables which reduces the current, which reduces the heating effect, which reduces energy loss. It also means the electrons are pushed all the way to its destination.

Transmission Cables

These transfer electricity.

Step Down Transformers

This reduces the pd from the transmission cables so are low enough for domestic use.

Static Charge

This is when insulating materials are rubbed against each other causing friction which moves negatively charged electrons from one material to another. The object that gains electrons becomes negatively charged and the object that loses electrons becomes positively charged. This means they become isolated objects.

Electrical Sparks

As the charge in an isolated object increases, the pd between the object and the earth increases, which may create a spark which jumps across the gap if this becomes high enough. The spark discharged the charged object and could be felt as an electric shock.

Isolated Objects

Objects that have no conducting paths to earth.

Electrostatic Forces

These are none contact forces that may cause attraction or repulsion.

Electric Fields

This is created around charged objects. (In diagrams, the arrows show the direction of the field and the distance between the lines represent the strength).

System

An object or group of objects.

Kinetic Energy Calculation

Kinetic Energy (J) = 0.5 x mass (kg) x (speed (m/s) ) squared

Gravitational Potential Energy Calculation

GPE (J) = mass (kg) x gravitation field strength (N/kg) x height (m)

Elastic Potential Energy Calculation

EPE (J) = 0.5 x spring constant (N/m) x (extension (m) ) squared

Internal Energy

The total kinetic and potential energy of all the particles that make up a system.

Specific Heat Capacity

The amount of energy required to raise the temperature of 1kg if a substance by 1°C.

Change in Thermal Energy Calculation

Change in thermal energy (J) = mass (kg) x SHC (J/kg °C) x temp change (°C)

Specific Heat Capacity Required Practical

1) set up apparatus.
2) measure the start temperature.
3) switch on the electric heater for 1 minute.
4) measure the end temperature.
5) measure the voltage and current to find the power.
6) repeat for different liquids.
7) calculate SHC.
8) compare results.

Dissipated

Spread out to the surroundings.

Closed System

A system where the total energy never changed but can be transferred from one store to another.

Uses for Unwanted Transfers

- Lubricant.
- Thermal insulation.
- Tightening if loose parts.

Thermal Insulators Required Practical

1) take 4 test tubes and wrap each one in a different type of insulation.
2) full each test tube with hot water and measure the start temp of each one.
3) start the stopwatch and record the temp every minute for 10 mins.
4) plot results in a graph.

Renewable Energy Resources

Energy sources which can be replenished.

Non Renewable Energy Resources

Energy sources which will eventually run out.

Biofuel Energy Resource

A renewable fuel which is used for transport and electricity generation. A large area of land is needed for growing fuel crops.

Wind Energy Resource

This is a renewable recourse which is used for electricity generation but does not provide a constant source of energy and can be noisy, as well as an eye saw.

Water Hydro Electricity Energy Recource

This is a renewable energy recourse which is used for electricity generation but requires a large area of land to be flooded.

Geothermal Energy Resource

This is a renewable energy recourse that is used for electricity and heat generation but is only available in a limited number of places where hot rocks can be found close to the surface.

Tidal Energy Resource

This is a renewable energy resource which is used to generate electricity but have a high set up cost.

Solar Energy Resource

This is a renewable energy resource which generates electricity but is a high set up cost and can't be used at night.

Water Waves Energy Resource

This is a renewable energy resource which is used for electricity generation but can be unreliable and can alter habitats.

Nuclear Fuel Energy Resource

This is a non renewable energy resource which is used for electricity generation and some military use but produces radioactive waste and has a high set up cost.

Coal Energy Resource

This is a non renewable energy resource which is used for electricity generation and heating but produces green house gases.

Oil Energy Resource

This is an non renewable energy resource which is used for transport and heating but can cause serious environmental damage if split.

Gas Energy Resource

This is a non renewable energy resource that is used for electricity generation and heat but produced CO2.

Density

This is a materials mass per unit volume.

Density Calculation

Density (kg/m cubed) = mass (kg) / volume (m cubed)

Density Required Practical

1) set up equipment.
2) record the height of the alter in the measuring cylinder and the mass of the solid / liquid being tested.
3) add the solid / liquid to the measuring cylinder.
4) record the new height in the measuring cylinder.
5) subtract the original height from the new height to give you the volume of the solid / liquid.
6) calculate the density.

Specific Latent Heat

Amount of heat needed to change the state of 1 kilogram of a substance WITHOUT a change in temperature.

Energy for a Change of State Calculation

Energy for a change of state (J) = mass (kg) x SLH (J/kg)

Latent Heat of Fusion

The energy needed for a substance to change from solid to liquid.

Latent Heat of Vaporisation

The energy needed for a substance to change from liquid to gas.

Heating and Cooling Graphs

This is a graph that indicates where energy is being used to change state. Where the line increases, that's where a change in state is occurring.

Constant Calculation

Constant = pressure (Pa) x volume (m cubed)

Atom

A tiny state of Mather with a radius of around 1 x 10 to the power of -10. Contains a nuclear mass up of protons and neutrons and is surrounded my electrons. Protons have an electrical charge of +1, electrons have -1 and neutrons have 0.

Ion

An atom that has lost or gained an election. If it has lost an electron it is a positive ion and if it gains an electron it is a negative ion.

Atomic Number

The number of protons in an atom of an element.

Mass Number

The total number of protons and neutrons in an atom.

Isotope

An atom with the same number of protons and a different number of neutrons from other atoms of the same element.

Plum Pudding Model

This is when an atom was thought to be a tiny sphere that could not be divided. It was made up my JJ Thompson.

Rutherford Experiment

In 1905, Rutherford bombarded a thin gold foil with alpha particles. If the plum pudding model was correct then the alpha particles would pass through. However, some of the particles were deflected showing that there must have been electrons surrounding the nucleus.

Nuclear Model

Model of the atom with a nucleus containing protons and neutrons and with electrons in the space outside the nucleus. By Rutherford.

Further Development of an Atom

Neil's Bohr and Chadwick (in different time periods) carried out a number of experiments to refine the nuclear model to provide the evidence of the model we use today.

The Activity of a Radioactive Source

The fate at which an atom decays, measured in becquerels (Bq). 1 Bq is the same as 1 count per second.

Alpha Radiation

This consists of 2 neutrons and 2 protons and is ejected from the nucleus. Can cause damage or passes through and is absorbed by living cells. Can be absorbed by paper so has a strong ionising power.

Beta Radiation

Had a high speed electron and is ejected from the nucleus as a neutron turns into a proton. Can caused damage is absorbed by living cells and can penetrate the body to inner organs. Has a reasonable ionising power so can pass through paper but can be absorbed by a sheet of 3-5mm aluminium.

Gamma Radiation

This used electromagnetic radiation and is emitted from the nucleus. It is likely to pass through living cells without being absorbed and causing ionisation and can pass through paper and a sheet of 3-5mm aluminium and can pass through a sheet of lead but a large amount of lead / many metres of concrete can absorb it. This means it has a poor ionising power.

Radioactive Contamination

This is the unwanted presence of materials containing radioactive atoms on other materials. It can cause irradiation and when using radio active sources you must wear appropriate clothing, never use bare hands and use the source at the lowest activity possible.

Irradiation

This is the process of exposing an object to nuclear radiation deliberately or by accident and does not cause the object to become radioactive.

Half Life

This is the average time it takes for half of a nuclei to decay. It is the time it takes for the count rate of the sample containing the isotope to fall to 50% of the original value. An isotope with a long half life is more stable and emits slowly so is less hazardous. An isotope with a short half life can be very unstable and emits Radiation very quickly so can be very hazardous.

Uses of Nuclear Radiation

- medical tracers.
- treat tumours.
- detect blockages.
- monitor kidney function

Background Radiation

This is radiation that is around us all the time. It can come from a range of sources and the amount a person experiences varies on location and occupations.

Nuclear Fission

This is the splitting of a large unstable nuclear and will never occur by itself. It will split into 3 smaller nuclei roughly the same size and emits 2 or 3 beauties, gamma rays and energy. The neutrons emitted can cause a chain reaction.

Nuclear Fusion

This is when 2 light nuclei join together to form a heavier nucleus. Some of the mass is converted into energy and some of this energy is emitted as radiation. It requires very high temperatures and pressures as it needs to overcome electrostatic repulsion and to bring the nuclei's close enough together for fusion to take place.

Nuclear Equations

This represents symbolically what occurs is nuclear reactions.