Physics - P2 | Flashcards

Question	Answer
Physics - P2	Nuclear Waste: High Level Waste - About 1% of total waste, is from fuel rods from core of reactor, highly radioactive and placed in a pool of water to minimise chance of fission occurring. To store they bury deep e.g. under the sea/ 1 mile underground in tightly sealed casks.
Nuclear Power: Advantages - No Co2, no carbon monoxide, quantity of waste is small, low fuel costs, local economy could benefit from the many jobs created.	Nuclear Power: Disadvantages - Risk of a major accident, nuclear waste is dangerous & long-lived, high construction & maintenance costs, large scale designs (lots of land used), power station spoils the look of the countryside, habitats will be destroyed, noise & air pollution.
Nuclear Waste: Medium Level Waste - About 20 % of the total waste, from cladding of fuel rods & radioactive sludge. can be contained in stainless steel drums and monitored areas about ground.	Nuclear Waste: Low level Waste - About 80% of the total waste, only slightly radioactive items e.g. protective clothing, medical equipment. It can be compacted and placed in containers then stored in specialized landfill sites.
Alpha - Helium nucleus, particle made up of 2 protons and 2 neutrons. Beta - High energy electron. Gamma - High frequency electromagnetic radiation.	Radiation: Alpha - Can be stopped by few cm of air or few sheets of paper. Beta - Pass through paper but can be stopped by few mm of aluminum. Gamma - Very penetrating most can be absorbed by many cm of lead some still gets through.
Uses of radiation: Radiotherapy, gamma rays, x-rays, steralisation of medical equiptement, [reserving food, controlling the thickness of paper, smoke detectors.	Effect of ionising radiation on living organisms: Can cause cancer or mutations in the cells (which can lead to cancer), & can lead to birth of deformed babies (future).
Nuclear Fusion: Joining together of 2 (or more) nuclei go form a larger atomic nuclei. It takes a huge amount of heat and energy to force the nuclei to fuse. More energy is produced by fusion than fission.	Nuclear Fission: Splitting atomic nuclei. Used in reactor to produce energy to make electricity. Usually Uranium 235 or plutonium 239. 1 neutron gets absorbed by U-235, 2 or 3 neutrons & 2 smaller daughter nuclei are produced.
Nuclear Reactors: (picture on back) reactor inside steel pressure vessel, surrounded by thick concrete to absorb radiation. Heat is carried away by boiled water to produce steam that drives turbines, steam cools to produce water which is returned to be re-heated.	Control rods used to absorb neutrons that produced in fission process. Rods can be raised or lowed, raised increase power, lowered decrease power. Moderator slows down fast neutrons, slow neutrons more likely to cause fission, so moderator increases power output.
Image: FullSizeRender (image/jpg)	Image: FullSizeRender (image/jpg)
Chain reactions: Uncontrolled - An enormous amount of energy & radiation is released, neutrons bombard pure uranium nuclei. This forms an atomic bomb.	Chain reaction: Controlled - The heat produced is used to make steam to generate electricity, neutrons bombard a mixture of u-235 and u-238 nuclei. This forms a nuclear reactor.
Kinetic energy: The energy an object has because of its movement. Kinetic energy(J) = 1/2 X Mass(Kg) X Velocity2 (m/s2)	Gravitational Potential energy: An object lifted above the ground gains PE/GPE. The additional height gives it the potential to do work when it falls. GPE (J) = Mass (Kg) X Gravitational field strength (N/Kg) X Vertical height (m)
Work: When a force moves and object, work is done on the object, resulting in the transfer of energy where: Work done (J) = Energy transferred (J)	Work done, force and distance moved are related by the following equation: Work done (J) = Force (N) X Distance moved in direction of force (m)
Power: The rate of doing work or the rate of transfer of energy. The grater the power, the more work done every second. Power (W) = Work done (J) Time taken (s)	Power is measured in watts (W) or joules per second (J/s). 1 watt = 1 joule per second.
Crumple zones: Areas of a vehicle that designed to deform & crumple in collision, increasing time interval for change in momentum. This means the force exerted on people in the car will be reduced, so less serious injuries.	Cushioning during impact: Air bags, soft seats etc. These reduce rate at which momentum changes and so reduced force exerted. Seat belt lock: Material stretches slightly, reduces change in momentum so reduces force on passenger.
Momentum: A measure of the state of movement of an object. It is dependent on 2 things. The mass (Kg) and the velocity (m/s) of an object. Momentum is a vector because velocity is a vector.	Momentum (Kg m/s) = mass (Kg) X Velocity (m/s)
Stopping distances: This depends on the thinking and the breaking distance. Stopping distance = Thinking distance + Breaking distance	Factors affecting breaking distance: Mass of the vehicle, the conditions the vehicle or the road (if it is wet or car has worn tyres), the drivers reaction time (the time taken for the driver to realise they need to apply the breaks, drinking alcohol?)
The slope of a distance-time graph represents the speed of the object . The steeper the gradient, the greater the speed. The speed can be calculated from the gradient. (Picture on back of card)	Image: unnamed1 (image/jpg)
Terminal velocity: The constant velocity reached by a falling body when the resultant force is zero. Unstable nuclei: Found in atoms that disintegrate; they emit radiation.	Moderator: Substance used to slow down fast neutrons and to increase power of a nuclear reactor. Radioactive: Materials containing unstable nuclei that spontaneously decay.
Protons: A positively charged subatomic particle with nearly the same mass as a neutron. Neutrons: A neutrally charged subatomic particle with nearly the same mass as a proton.	Half-life: The time taken for the undecayed nuclei in radioactive material to decay. Isotopes: Atoms of the same element that have the same number of protons but a different number of neurons.
Earthing: Enables electrons to flow from one object to earth to allow discharge. Electron: A negatively charged subatomic particle with a very tiny mass.	Fission: The splitting of large atomic nuclei that produces a large amount of energy. Fusion: The joining together of small atomic nuclei, producing a large amount of energy.
Daughter nucleus: A nucleus produced by radioactive decay of another another nucleus (the parent). Control rods: Devices used to control the power of a nuclear reactor.	Alpha particles: Consist of 2 protons and 2 neutrons (a helium nucleus); emitted from the nuclei of radioactive substances during alpha decay.

Next up

Physics - P2

Description

Resource summary

Similar

	Created by HeidiCrosbie over 9 years ago