# P2 Revision (From Mark Scheme)

This is my P2 mindap designed to help people with their exam. The good thing about this Mindmap is that it made from the mark scheme answers and uses the wording. It should be immensly helpful!

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• Physics P2 Mark Scheme Revision
• Structure of alpha particles: two protons and two neutrons from a helium nucleus
• Beta Particles are electrons emitted from an unstable nucleus
• Beta is sometimes produced from a radioactive isotope because the neutron splits to form a proton and an electronr
• Life history of a star like our sun:                1) formed from dust and gas                        2) pulled together by gravity            3) massive so very large gravitational force              4) hydrogen turns to helium during nuclear fusion  this releases energy            5) high temperature creates high pressure          6) then expands into a red giant          7) then contracts to form a dense white dwarf
• Lifetime of a main sequence star relates to its mass (lower mass = longer life) this is because greater mass means greater core temperature. greater core temperature means greater rate of fussion. Increase in mass produces proportionally much greater rate of fussion
• Forces that allow a stable star to exist is gravity pulling matter together. Then high pressure that create expansion force. these forces then balance. The star then expands greatly since expansion force is greater than gravity. This will in turn then form a red giant after. The red giant will then collapse inwards and explode outwards, this is called a super nova. May leave a neutron star. this leaves a small dense object called a black hole
• the Sun can radiate huge amounts of energy after billions of years as loss of mass results in huge energy release (loss of mass when hydrogen converted into helium). Small loss of mass results in a HUGE energy release
• Force
• Food processor produces sound when it is switched on because it vibrates.
• Weight is caused by gravity and the attraction between mass of object and the mass of earth.
• Example of balanced forces: the weight of a brick does not make it move downwards on a table because it is balanced by upwards force of the table
• Electricity
• When voltage across the bulb falls to half, the current through the bulb falls by less than half. this is because resistance of the lamp decreases because filament cools.
• A device is more economic when it uses less energy or (possibly) if it gets the jobs done faster.
• Structure of alpha particles: two protons and two neutrons from a helium nucleus
• Beta Particles are electrons emitted from an unstable nucleus
• Beta is sometimes produced from a radioactive isotope because the neutron splits to form a proton and an electronr
• Life history of a star like our sun:                1) formed from dust and gas                        2) pulled together by gravity            3) massive so very large gravitational force              4) hydrogen turns to helium during nuclear fusion  this releases energy            5) high temperature creates high pressure          6) then expands into a red giant          7) then contracts to form a dense white dwarf
• Lifetime of a main sequence star relates to its mass (lower mass = longer life) this is because greater mass means greater core temperature. greater core temperature means greater rate of fussion. Increase in mass produces proportionally much greater rate of fussion
• Forces that allow a stable star to exist is gravity pulling matter together. Then high pressure that create expansion force. these forces then balance. The star then expands greatly since expansion force is greater than gravity. This will in turn then form a red giant after. The red giant will then collapse inwards and explode outwards, this is called a super nova. May leave a neutron star. this leaves a small dense object called a black hole
• the Sun can radiate huge amounts of energy after billions of years as loss of mass results in huge energy release (loss of mass when hydrogen converted into helium). Small loss of mass results in a HUGE energy release
• Electricity
• When voltage across the bulb falls to half, the current through the bulb falls by less than half. this is because resistance of the lamp decreases because filament cools.
• A device is more economic when it uses less energy or (possibly) if it gets the jobs done faster.