Physics Paper 1 GCSE Flashcards
What is a system?
an object or group of objects
How can you calculate kinetic energy?
0.5 x mass x (speed)2
How can you calculate amount of elastic potential energy stored in a stretched spring?
0.5 x spring constant x (extension)2
How do you calculate gravitational potential energy?
mass x gravitational field strength x heaight
How do we calculate change in thermal energy?
mass x specific heat capacity x temperature change
What is the specific heat capacity of a substance?
amount of energy required to raise the temperature of one kilogram of the substance by one degree celsius
What is power?
rate at which energy is transferred or the rate at which work is done
How can you calculate power?
energy transferred/timer
work done/ time
What is an energy transfer of 1 joule per second equal to?
power of 1 watt
How can energy be used?
transferred usefully, store or disspated
What can energy not be?
created or destoyed
The higher the thermal conductivity of a material the higher the rate of…
energy transfer by conduction across the material
How do we calculate efficiency?
useful output/total input
What are the main energy resources available of earth?
fossil fuels (coal, oil and gas) nuclear fuel bio fuel wind hydroelectricity sun water waves geothermal tides
What is a renewable energy resource?
One that is being replenished as it is used
What is a step up transformer used for?
increasing the voltage to several hundred thousand volts
reduce current and reduces energy lost by heating the wires
increase potential diffeence
What does a step down transformer do?
Reduce voltage down to several hundred volts to a safe level
What does the national grid consist of?
a system of transformers and high voltage cables
What is the big problem getting energy to homes?
Energy is always lost in the power cables. The bigger the distance between the power station and the homes the greater energy loss
Why do they increase the voltage to a high number in the step up transformer?
less energy is lost in the power cables at high voltage then at low voltages
What must a closed circuit include to allow an electrical charge to flow through it?
source of potential difference
What is the size of the electric current?
Rate of flow of electrical charge
How do you calculate charge flow?
current x time
What is the symbol for charge flow?
coulombs
What does the current through a component depend on?
resistance of the component and potential difference across the component
The greate the resistance….
the smaller the current given potential difference across the component
How do you calculate potential difference?
current x resistance
The current through an ohmic conductor at a constant temperature is…..
directly proportional to the potential difference across the resistor
The resistance of components such as lamps, diodes, thermistors and LDRs is…
not constant
The resistance of a filament lamp increases as the temperature of the filament ….
increases
The current through a diode flows….
in one direction only
The diode has a ….
very high resistance in the reverse direction
The resistance of a thermistor decreases as the temperature…
increases
The applications of thermistors in circuits is…
required
The resistance of an LDR decreases as light intensity…
increases
What are the two ways of joining electrical components?
series and parallel
For components connected in series there are
- there is the same current through each component
- the total potential difference of the power supply is shared between the components
- the total resistance of two components is the sum of the resistance of each component.
For components connected in parallels there is
- the potential difference across each component is the same • the total current through the whole circuit is the sum of the currents through the separate components
- the total resistance of two resistors is less than the resistance of the smallest individual resistor.
What type of current is mains electricity?
alternative current
What is the UK domestic electricity supply frequency and voltage?
50Hz
230V
What colour is the live wire?
brown
What colour is the neutral wire?
blue
What colour is the earth wire?
green and yellow stripes
What does the live wire carry?
alternating potential difference from the supply
What does the neutral wire do?
completes the circuit
What is the earth wire?
safety wire to stop the appliance becoming live
What is the potential difference between the live ire and the earth?
about 230 V
The neutral wire is at what?
earth potential (0V)
What is the earth wire at and when does it carry a current?
0 V it only carries a current if there is a fault
What are two equations for power?
potential difference x current
(current)2 x resistance
What are everyday electrical appliances designed to do?
bring about energy transfer
What does the amount of energy an appliance transfers depends on what?
how long the appliance is switched on for and the power of the appliance
When is work done?
when charge flows in a circuit
How do you calculate energy transferred?
power x time
charge flow x potential difference
What is the symbol for charge flow?
coulombs C
How is electrical power transferred from power stations to consumers?
The National Grid
What does a charged object create around itself?
electric field
Where is the electric field strongest?
close to the charged object
What does the second charge object placed in the field experience?
a force
When does the force get stronger between the two objects?
as the distance between the objects decreases
How do calculate density?
mass/volume
How is energy stored inside a system?
by the particles that make up the system this is called internal energy
What is internal energy?
total kinetic energy and potential energy of all the particles that make up the system
what does the increase in temperature depend on?
the mass of the substance heated, type of material and the energy input
How do you calculate the change in thermal energy?
mass x specific heat capacity x temperature change
What is the specific heat capacity of a substance?
amount of energy required to raise the temperature of one kilogram of the substance by one degree
What is the specific latent heat of a substance?
amount of energy required to change the state of one kilogram of the substance with no change of temperature
What is the equation for energy for a change in state?
mass x specific latent heat
What is the energy needed for a substance to change state called?
Latent heat
When a change of state occurs…
The energy supplied changes the energy stored but not the temperature
What is the specific lantent heat of fusion?
change of state from solid to liquid
What is the specific latent heat of vaporisation?
change of state from liquid to vapour
The temperature of the gas is related to what?
the average kinetic energy of the molecules
The molecules of a gas are in….
constant random motion
Changing the temperature of a gas held at constant volume changes what?
pressure exerted by the gas
Doin work on a gas increases what?
the internal energy of the gas and cause an increase in the temperature of the gas
Work is the transfer of what?
energy by a force
What is the basic structure of an atom?
positively charged nucleus composed of both protons and neutrons surronded by negatively charged electrons
The radius of a nucleus is less than what?
1/10000 of the radius of an atom
Most of the mass of an atom is concentrated where?
nucleus
When might the electron arrangement change?
absorption of electromagnetic radiation or by the emission of electromagnetic radiation
In an atom the number of electrons is equal to the number of what?
protons
All atoms of a particular element have…..
the same number of protons
The number of protons in an atom of an element is called what?
atomic number
The total number of protons and neutons in an atom is called what?
mass number
What is the top number of an element?
Mass number
What is the bottom number of an element?
Atomic number
Atoms of the same element can have different number of what and what are they called?
neutrons and they are called isotopes
Activity is measured in what?
becquerel (Bq)
What is count rate?
number of decays recorded each second by a detector
The nuclear radiation emitted may be?
an alpha particle
a beta particle
a gamma ray
a neutron
What does an alpha particle consist of?
consists of two neutrons ad two protons
What does a beta particle consist of?
a high speed electron ejected from the nucleus as a neutron turns into a proton
What is a gamma ray?
electromagnetic radiation from the nucleus
Nuclear equations are used to represent what?
radioactive decay
The emission of the different types of nuclear radiation may cause what?
a change in the mass and/or the nucleus
Beta decay does not cause the mass of the nucleus to change but does cause the charge of….
the nucleus to increase
The emission of a gamma ray does ….
not cause the mass or the charge of the nucleus to change
Radioactive decay is….
random
What is radioactive contamination?
the unwanted presence of materials containing radioactive atoms on other materials
The hazards from contamination is due to what?
the decay of contaminating atoms
What is Irradiation?
process of exposing an object to nuclear radiation. The irradiated object does not become radioactive
What is alpha radiation?
least penetrating. It can be stopped by a sheet of paper
What is beta radiation?
Can penetrate air and paper. It can be stopped by a tin sheet of aluminium
What is Gamma radiation?
most penetrating. Even small levels can penetrate air, paper or thin metal. Higher levels can only be stopped by many cm of lead or many metres of concrete
What is the order or radiation weakest to strongest?
Alpha
Beta
Gamma
What is alpha radiation used for?
smoke detectors
What is beta radiation used for?
tracers and monitoring the thickness of materials
Why may doctors use tracers for?
medical imaging. Radiation detectors placed outside the body detect the radiation emitted and build up an image of the inside of the body
Why would they use beta radiation in industry?
detectors that monitor and control the thickness of materials. It then sends signals to the equipment that adjust the thickness of the material
Where is gamma radiation used?
used in the treatment of cancer, testing equipment and sterilising medical instruments
How do you calculate weight?
mass x gravitational field strength
How do you calculate work done?
force x distance (along the line of action of the force)
How do you calculate the force applied to a spring?
spring constant x extension
How do you calculate moment of a force
force x distance
How do you calculate pressure?
force normal to a surface / area of that surface
How do you calculate distance travelled?
speed x time
How do you calculate acceleration?
change in velocity / time taken
How do you calculate resultant force?
mass x acceleration
How do you calculate momentum?
mass x velocity
What is a thermistar used for?
Central heating
Only lets current flow out at certain temperature
What are the uses of Light dependant resistor?
Street lights
Security lights
What does the plum pudding model show?
A positive ball with negative bits dotted through out it
What does the nuclear atom show?
Build up of positive atom with negative atoms around the outside so the majority of the atom was empty space
Who designed the plum pudding model?
Rutherford
Who designed the nuclear model?
Bohr
