AQA Physics Paper 1

sound energy

Energy caused by an object's vibrations

thermal energy

The total energy of motion in the particles of a substance

chemical energy

A form of potential energy that is stored in chemical bonds between atoms.

nuclear energy

the potential energy stored in the nucleus of an atom

electrical energy

Energy caused by the movement of electrons.

light energy

Energy in the form of moving waves of light

kinetic energy

energy of motion

gravitional potential energy

potential energy that depends on the height of an object

elastic potential energy

the energy of stretched or compressed objects

conservation of energy

law that says energy cannot be created or destroyed, but can change forms

uses of friction

- rubbing hands for warmth

- break pads on bikes

Efficiency =

Useful Energy Output / Total Energy Input

Increase efficiency

- add lubricant

- reduce friction

internal energy

the sum of the kinetic and potential energies of all particles in the system

Conduction

The direct transfer of heat from one substance to another substance that it is touching.

Convection

The transfer of thermal energy by the circulation or movement of a liquid or gas

convection current

a current caused by the rising of heated fluid and sinking of cooled fluid

Insulator

A material that does not allow heat or electrons to move through it easily.

Infra red radiation

Electromagnetic waves of heat energy.

Radiation

Energy that is radiated or transmitted in the form of rays or waves or particles.

greenhouse effect

CO2 and other greenhouse gases in the atmosphere absorb long wavelength radiation radiated from the Earth's surface and prevent it escaping.

black

good absorber of radiation

white

poor absorber of radiation

specific heat capacity

the energy required to raise the temperature of one gram of a substance by one degree Celsius

Reduce heat loss from homes

- loft insulation (fibre glass is a good insulator)

- cavity wall insulation (foam prevents convection currents)

- aluminum foil behind radiator (reflects radiation)

- double glazing (vacuum slows conduction and radiation)

energy transfer

power x time

non-renewable energy

A natural resource such as coal, gas, or oil that, once consumed, cannot be replaced.

renewable energy

A resource that has a theoretically unlimited supply and is not depleted when used by humans.

solar, wind, geothermal, hydropower, tidal, wave, nuclear, biofuel

dis: unreliable (except hydroelectric and geothermal)

nuclear power

energy from splitting Uranium atoms.

dis: nuclear waste, expensive

carbon neutral

an activity that does not change atmospheric carbon dioxide concentrations

bulb

resistor

variable resistor

light emitting diode

switch

volt meter

measures potential difference

ammeter

measuring the current

resistance

A material's opposition to the flow of electric current.

current

A flow of electric charge.

Density formula

mass/volume

freezing

liquid to solid

melting

solid to liquid

condensing

gas to liquid

boiling

liquid to gas

sublimating

solid to gas or gas to solid

conservation of mass

the principle stating that matter is not created or destroyed during a chemical reaction

physical change

A change in a substance that does not involve a change in the identity of the substance

latent heat

the energy absorbed or released during a change in state

Specific Latent Heat

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

specific latent heat equation

energy = mass x specific latent heat

specific latent heat of fusion

the energy needed to change a unit mass from the solid to the liquid phase at constant temperature

specific latent heat of vaporisation

the energy needed to change a unit mass from the liquid to the vapour phase at constant temperature

Pressure equation

P=F/A

pressure change in liquids

pressure increases as you go deeper because you have more liquid pushing down from above.

the greater the density the greater the pressure

Unit of pressure

Pascals, Pa

OR

Newtons per metre squared, N/m^2

upthrust

A force that pushes things up in liquids and gases.

sinking

weight > upthrust

nucleus

the center of an atom

mass number

the sum of the number of neutrons and protons in an atomic nucleus

isotopes

atoms of the same element that have different numbers of neutrons

why atoms are radioactive

they have too many neutrons and become unstable.

alpha radiation

2 protons and 2 neutrons

alpha calculations

mass number -4 proton number -2

beta radiation

fast-moving electrons

beta calculations

mass number 0 proton number +1

gamma radiation

electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength

ion

atom that has a positive or negative charge

order of ionising power from most to least

alpha > beta > gamma

penetrating power alpha

sheet of paper, couple of cm

penetrating power beta

aluminium

penetrating power gamma

thick lead or concrete

use of alpha radiation

smoke alarm

uses of beta radiation

making paper and aluminium the right thickness

half-life

the period of time in which half of a radioactive substance decays

uses if gamma radiation

find leaks in pipes

carbon dating

a scientific method used to determine the age of an artifact

Plum Pudding Model

The model of an atom in which there is a positively charged ball with electrons dotted through it.

Ernst Rutherford

Gold foil experiment. Most alpha particles passed straight through but some were deflected a little and a lot disproving the plum pudding model.

background radiation

nuclear radiation that occurs naturally in the environment

Sources of background radiation

Radon gas, cosmic rays, rocks, building materials, medical x-rays, food, nuclear industry

nuclear fission

nuclei of isotopes split apart when struck by neutrons produces a large amount of energy.

State two definitions of

radioactive half-life

.

1. The half-life is the (average)

time taken for half of the

radioactive nuclei in a

sample to decay

.

2. The half-life is the time

taken for the activity (or

count rate) of a radioactive

sample to fall to half its

original value.

What is the

difference between the

specific heat capacity and

the specific latent heat of a

material

Specific heat capacity is the energy

needed to raise the temperature

of 1 kg of the material by 1 °C,

with no change of state.

Specific latent heat is the energy

needed to change the state of

1 kg of the material, with no

change in temperature

Complete the gaps

in the sentences.

Choose from:

greater smaller

more less

Beta radiation has a … ionising

power than alpha radiation and

so is … penetrating and has a …

range in air.

A beta source a few metres away

from you is therefore likely

to be … dangerous than an

alpha source at that distance.

Beta radiation has a smaller

ionising power than alpha

radiation and so is more

penetrating and has a greater

range in air.

A beta source a few metres

away from you is therefore

likely to be more dangerous

than an alpha source at that

distance

List the factors that

affect the size of the force on

a current-carrying conductor

in a magnetic field

The magnetic flux density, the

size of the current and the

length of the conductor that is

in (and perpendicular to) the

magnetic field

A magnetic material brought

close to a magnet …

… is always attracted to the

N pole of the magnet.

… is attracted to the

nearest pole of the magnet.

A magnetic material brought

close to a magnet is attracted to

the nearest pole of the magnet.

The strong magnetic field near

either magnet pole makes the

nearby magnetic material an

induced magnet and this

always causes attraction.

State the behaviour of an LDR in

a circuit when the light intensity

falling on it decreases.

An LDR is a light-dependent

resistor. Its electrical

resistance increases when the

light intensity decreases

State the equation

for calculating the

electrical power P of a device

of resistance R, when the

current through it is I, and

state the unit of power.

Power P = I^2 R

The unit of power is the watt,

W (equivalent to J/s)

What is the

equation relating

the potential difference across,

the current through and the

resistance of a component in a

circuit

Potential difference

= current × resistance

True or false?

If all of the electrical

energy supplied to

an efficient kettle is used to

heat the water, this equation

determines the change in

temperature of the water,

∆θ. I V t = m c ∆θ

True.

The electrical energy supplied to

the kettle is power × time = I V t.

The rise in temperature of the

water ∆θ depends on the mass m

and the specific heat capacity c of

the water. Energy change

of water = m c ∆θ.