|What are forces measured in?
|If there are multiple forces acting on an object, they can be replaced as a single force, known as the ____________ ________.
|If there is a non-zero resultant force acting an an object, what effect will be observed?
|An acceleration in the direction of the resultant force
|How do you work out the speed of something?
|What extra factor does velocity have over speed?
|What does the slope/gradient of a velocity-time graph show?
|The area underneath the line in a velocity-time graph represents ______ __________ ____________ ________________.
|The total distance travelled
|Friction occurs when...
|- An object moves through a medium, e.g. air or water - Surfaces slide past each other
|How do you work out the stopping distance?
|Thinking distance + Braking Distance
|What two forces do all falling objects experience?
|A downward force, called weight (W) An upward frictional force, e.g. air resistance or drag through a fluid (R)
|What is meant by terminal velocity?
|Constant speed reached when the upward resistive force balances the downward force (weight)
|What is the name given to energy that is stored in an elastic spring?
|Elastic potential energy
|What is 'work done' (in terms of energy)?
|what is the gravitational potential energy?
|The energy an object has due to its vertical position in the gravitational field
|What is meant by the phrase 'conservation of momentum'?
|Total momentum before = total momentum after
|An electric current flowing through a circuit is...
|A flow of electric charge
|An electric current will flow through an electrical component is there is a...
|potential difference (voltage) across the ends of the component.
|What two factors affect the amount of current that flows through a component?
|- The potential difference across the component - The resistance of the component
|As the amount of light falling on a light dependent resistor (LDR) increases, the resistance...
|As the temperature of a thermistor increases, its resistance...
|As the temperature of a filament lamp increases, and the bulb gets brighter, then the resistance of the lamp...
|Why is this?
|This is due to the greater vibrations of the metallic ions in the filament wire gradually preventing the flow of free electrons.
|TRUE OR FALSE: A diode allows current to flow through it in only one direction.
|TRUE This is because it has a very high resistance in the reverse direction
|What colour is the: Earth Wire? Neutral Wire? Live Wire?
|Green and Yellow Blue Red
|Name two devices that give protection when an electrical fault occurs?
|Fuse Circuit Breaker Residual Current Circuit Breaker
|What is the name of the rate at which energy is transferred?
|What is the amount of electrical charge that passes any point in a circuit measured in?
|What is the Relative Mass and Relative Charge of: A Proton A Neutron An Electron
|Proton: RM= 1 RC= +1 Neutron: RM= 1 RC= 0 Electron: RM = 1/2000 RC= -1
|What are isotopes?
|Atoms of the same element that have different numbers of neutrons
|What do isotopes of atoms that have too many or too few neurons form?
|What is radioactive decay known as?
|What happens in Alpha Decay?
|The original atom decays by ejecting an alpha particle from its nucleus. An alpha particle is a huge particle. It's identical a helium nucleus, consisting of two protons and two neutrons.
|What happens in Beta Decay?
|The original atom decays by changing a neutron into a proton and an electron. The electron emitted is called a beta particle, with the symbol β.
|What may happen when radiation collides with neutral atoms or molecules in a substance?
|The atoms or molecules may become charged due to electrons being 'knocked out' of the orbiting structure. This leaves the atoms or molecules as ions, or as charged particles.
|What is the charge of an alpha particle and a beta particle?
|+2 for Alpha Particle -1 for Beta Particle
|Alpha Particle: What is its ionising power? What does it take it be stopped? Is it affected by Electric and Magnetic fields?
|Strong Stopped by paper, skin or 6cm of air Yes, but opposite to beta particles
|Beta Particle: What is its ionising power? What does it take it be stopped? Is it affected by Electric and Magnetic fields?
|Weak Stopped by 3mm of aluminium Yes, bent strongly, but opposite to alpha particles
|Gamma Particle: What is its ionising power? What does it take it be stopped? Is it affected by Electric and Magnetic fields?
|Very Weak Reduced, but not stopped by lead No
|What is the half life of a radioactive isotope?
|A measurement of the time it takes for the rate of decay to halve OR The time required for half of the original population of radioactive atoms to decay
|What is Nuclear Fission and what is it used for?
|The splitting of an atomic nucleus. It's used in nuclear reactors to release energy to make electricity.
|What is meant by the term 'chain reaction'?
|Neutrons released from the initial reaction go on to interact with other nuclei producing even more neutrons each time.
|What is Nuclear Fusion?
|The joining together of two or more atomic nuclei to form a larger atomic nucleus.
|What are the steps in a star's formation?
|Stars, like our sun, form when enough dust and gas from space are pulled together by gravitational forces, which always attract each other. This forms a nebula where a protostar is then formed. Forcing material together increases the temperature and density, and nuclear fusion reactions start releasing huge amounts of energy. Eventually the forces balance to make a star stable. The newly formed star becomes a main sequence star.
|What happens when a star about the size of the sun runs out of hydrogen?
|1. The Star leaves the main sequence and becomes a red giant 2. It continues to cool before collapsing under its own gravity to become a white dwarf. 3. It continues to cool and loses its brightness to become a black dwarf.
|What happens when a star much larger than the sun runs out of hydrogen?
|1. The star leaves the main sequence and becomes a red super giant. 2. It cools but shrinks very rapidly and explodes as a supernova. This explosion releases massive amounts of energy, dust and gas into space, and forms elements heavier than iron. 3. Depending on the precise mass of the remnants either a neutron star or a black hole is formed. 4. The dust and gas form new stars.