Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
79 Cards in this Set
- Front
- Back
|
What is the Resultant Force? |
The sum of forces acting upon an object |
|
|
What does the gradient of a distance-time graph represent? |
Speed |
|
|
What is velocity of an object? |
Speed in a given direction |
|
|
What does the gradient of a velocity-time graph represent? |
Acceleration |
|
|
What does the area underneath a velocity-time graph show? |
Distance Travelled |
|
|
What is the equation for stopping distance? |
Thinking Distance + Braking Distance |
|
|
What factors affect the driver's reaction time? (4) |
Tiredness Alcohol Drugs Distractions |
|
|
What happens when the brakes of a vehicle are applied? (2) |
Friction reduces kinetic energy of the vehicle Temperature of the brakes increase |
|
|
What factors affect a vehicle's braking distance? (3) |
Poor road conditions (eg. ice) Poor weather conditions Poor condition of brakes or tires |
|
|
What is terminal velocity? |
When the kinetic energy of an object is equal to resisting forces so the resultant force is equal to zero |
|
|
What type of energy does a spring hold? |
Elastic Potential Energy |
|
|
What is the rule for elastic objects? |
The extension of an elastic object is directly proportional to the force applied, provided that the limit of proportionality is not exceeded |
|
|
What is work done? |
When a force is applied to make an object move, work is done. Energy is transferred |
|
|
What is power? |
Work done or energy transferred in a given time |
|
|
What is Gravitational Potential Energy? |
Energy an object has in virtue of its position in a gravitational field
|
|
|
What is momentum? |
A property of moving objects as a product of mass and velocity |
|
|
What is conservation of momentum? |
total momentum before the event = total momentum after the event |
|
|
What is static electricity? |
When two objects rub against each other and electrons are passed from one object to another |
|
|
Like charges ______ and opposite charges _______ |
repel, attract |
|
|
Why can't a metal conduct static electricity |
The electrons (electric charge) can easily move through the metal. This is due to delocalised electrons in the metal. |
|
|
REVISE CIRCUIT SYMBOLS BEFORE CONTINUING |
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/circuitsrev1.shtml |
|
|
What is the relation between current and potential difference? |
They are directly proportional at a constant temperature across the resistor |
|
|
What is the relation between current and resistance |
The greater the resistance, the lower the current |
|
|
Give the properties of a series (no branches) circuit (3) |
Total resistance is the sum of resistance of each component Total potential difference is shared between the components Current is the same for each component |
|
|
Give the properties of a parallel (branched) circuit (2) |
Potential difference is the same for each component Total current is the sum of current of each component |
|
|
As the temperature of the filament increases, the ________________________ |
resistance of filament bulb increases |
|
|
What shape is a current-potential difference graph |
S-Shaped |
|
|
Explain resistance in terms of electrons and ions |
Moving electrons as charge flowing through a metal can collide with ions withing the metal. When a metal is heated, the ions vibrate more, so the frequency of collisions is increased, decreasing the current. |
|
|
The resistance of an LDR decreases as _______________________ |
Light intensity decreases |
|
|
The resistance of a thermistor decreases as _______________________ |
Temperature increases |
|
|
What is an LED and how does it save energy over a filament bulb? (2) |
An LED (Light emitting diode) emits light when a current flows through it in the forward direction They use a lower current so save energy |
|
|
What is a D.C. and give two examples |
A direct current is a current that is always passing in the same direction eg. Cells and Batteries |
|
|
What is an A.C. and give an example |
An alternating current is one that is constantly changing direction eg. Mains electricity |
|
|
Give the frequency and voltage of UK mains electricity |
50 Hertz 230 Volts |
|
|
Draw the structure of a three-pin plug |
|
|
|
What is the difference between a two-pin and a three-pin plug? |
A two-pin plug has no earth wire |
|
|
What is the job of a fuse? |
It melts when the current gets too high in the live wire, breaking the circuit |
|
|
What is the job of an RCCB? How does it work? |
Breaks the current if it gets too high by detecting the difference between the live wire and the neutral wire |
|
|
Appliances with metal cases are usually _______ |
earthed |
|
|
Why do some products only have a two-pin plug? |
They are double-insulated |
|
|
How does cable thickness affect fuse rating? |
The higher the cable thickness, the higher the fuse rating |
|
|
How do Compact Fluorescent Lamps waste less energy than filament bulbs? |
They produce less waste heat energy |
|
|
What is power? |
The rate at which energy is transferred by an appliance |
|
|
What are ions? |
When atoms lose or gain electrons to become charged particles |
|
|
What is the atomic number? |
The total number of protons |
|
|
What is the mass number? |
The total number of protons and neutrons |
|
|
Each isotope has a different number of what? |
Neutrons |
|
|
What are radioactive substances |
Substances that give out radiation from the nuclei of their atoms all the time |
|
|
Give examples of background radiation (4) |
Rocks Cosmic Rays Fallout from nuclear weapons tests Nuclear Accidents |
|
|
What is an alpha particle made of? |
2 neutrons, same as helium nucleus |
|
|
What is a beta particle made of? |
An electron from the nucleus |
|
|
What is a gamma particle made of? |
Electromagnetic Radiation |
|
|
What is an alpha particle stopped by? |
A sheet of paper |
|
|
What is a beta particle stopped by? |
Thin sheet of aluminium |
|
|
What is a gamma particle stopped by? |
Several centimeters of lead, or many meters of concrete |
|
|
What is the range of alpha radiation in air? |
Few centimetres |
|
|
What is the range of beta radiation in air |
Many centimetres |
|
|
What is the range of a gamma particle in air? |
Many meters |
|
|
What is the ionizing power of an alpha particle? |
Very High |
|
|
What is the ionizing power of a beta particle? |
High |
|
|
What is the ionizing power of a gamma particle? |
Low |
|
|
What is the atomic mass and number of a beta particle? |
Atomic number = -1
Atomic mass = 0 |
|
|
What is the atomic mass and number of a alpha particle? |
Atomic number = 4 Atomic mass = 2 |
|
|
What is the charge, of an alpha particle? How does it react to an electrical/magnetic field? |
Charge is +2 It is repelled from the positive pole and attracted towards the negative pole |
|
|
What is the charge, of an beta particle? How does it react to an electrical/magnetic field? |
Charge is -1 It is repelled from the negative pole and attracted towards the positive pole |
|
|
What is the half-life of a radioactive isotope |
The time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate from a sample containing the isotope to fall to half its initial level |
|
|
What are the two most common fissionable substances? |
uranium-235 and plutonium-239 (mainly uranium) |
|
|
What is nuclear fission? |
Splitting of an atomic nucleus |
|
|
Explain nuclear fission in three steps |
The substance absorbs a neutron The nucleus splits into two smaller nuclei and two or three neutrons and energy is released The neutrons may start a chain reaction |
|
|
What is nuclear fusion? |
The joining of two atomic nuclei to form a larger one |
|
|
How is energy released in stars? |
Nuclear fission |
|
|
What is the protostar made of? |
Dust and gas from space |
|
|
How does the protostar form the main sequence star? |
The dust and gas is pulled together by gravitational attraction to form stars. |
|
|
How are planets formed? |
Smaller masses are attracted by a larger mass to become planets |
|
|
What is the sequence of a regular sized sun? (5) |
Protostar Main sequence star Red Giant White Dwarf Black Dwarf |
|
|
What is the sequence of a huge sun? (5) |
Protostar Main sequence star Red super giant Supernova Neutron star/black hole |
|
|
During fusion, what elements turns into what element in stars when it starts out? |
Hydrogen to helium
|
|
|
How are naturally occurring elements till iron formed? |
During a main sequence star |
|
|
How are naturally occurring elements heavier than iron formed? |
In a supernova |
