670 likes | 888 Views
PDP Physics. N uclear fusion and Radioactivity. Image: http://en.wikipedia.org/wiki/Exoplanet. Generating electricity. Electricity generation. wind hydroelectric coal oil natural gas biofuel solar power geothermal (nuclear). Electricity generation presentation.
E N D
PDP Physics Nuclearfusion and Radioactivity Image: http://en.wikipedia.org/wiki/Exoplanet
Electricity generation • wind • hydroelectric • coal • oil • natural gas • biofuel • solar power • geothermal • (nuclear)
Electricity generation presentation • in a group of 2 or 3 • on google drive or prezi • about 3-4 minutes • Your presentation should answer the following: • How does it work? • What energy conversions are involved? • How efficient is it? • How much power does a typical plant produce? • How much power is generated in total in Sweden? • Where do the resources originate? • What are the benefits of this method of generating electricity? • What are the problems? How significant are they? • What is the future potential?
Electricity bill in kWh http://www.dolceta.eu/sverige/Mod6/Elrakningen.html
kiloWatthours are units of energy 1kWh = 1kW used for 1 hour Energy = power × time 1kWh ≈ 4MJ
Comparing different energy uses Fluctuations kWh per day kWh/d is a unit of power power = energy/time
Energy density of a fuel energy density = energy released mass of fuel energy density in MJ/kg Uranium 79 500 000MJ/kg Coal 24MJ/kg
Efficiency What percentage of the energy comes out as useful energy? efficiency = energy out × 100 energy in
Atoms • atomic number • mass number • relative atomic mass • electron shell • isotope • atomic mass unit, u • elementary charge, e • electronVolt, eV
Atomic structure Atomic number, Z Mass number, A 7 Li 3
Atomic nucleus Strong nuclear force (protons and neutrons) Electrostatic force (protons and electrons)
An elementary particle has no internal structure and is not made from smaller constituents.A composite particle is made from elementary particles.
Particles are made of particles A proton is built from 3 quarks
composite: atom proton neutronelementary: electron quark neutrinocomposite: atom proton neutronelementary: electron quark neutrino proton
Background radiation • is the natural radiation from materials in the environment including rocks, the air and living organisms • varies with location
What is the relationship between Z and N? • Research the stable isotopes of as many atoms as possible and plot a graph of N against Z • Plot a trendline and write down the gradient. Explain what the gradient means for this graph. • Explain why this pattern occurs using ideas about the strong nuclear force and the electrostatic force.
Nuclear Radiation Stable or unstable?
Geiger-Müller tube (GM tube) Image: http://en.wikipedia.org/wiki/Geiger_counter
Nuclear symbols The nucleus of an atom can be represented as: AZX • A is the atomic mass (number of protons + neutrons) • Z is the atomic number (number of protons- see Periodic Table) • X is chemical symbol (see Periodic Table)
Alpha decay 21986Rn 21584Po + 42α Z decreases by 2 A decreases by 4
Write nuclear decay equations for the alpha decay of: Polonium-218 Gold-196
Beta decay 146C 147N + 0-1β + 00ν Z increases by one A constant
Write nuclear decay equations for the beta decay of: Phosphorous-32 Iodine-131
Radioactivity α-decay β-decay γ decay
Half life 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 starting level Images: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/atoms_radiation/nuclearradiationrev7.shtml
Activity • The activity of a sample, A, is the number of decays in one second. • The decay constant, λ, is the probability that a single nucleus will decay in one second. • N is the total number of unstable nuclei
Artificial transmutations • a nucleus can ‘capture’ another particle • this is the only way to speed up radioactive decay
Bang! Trinity test • plutonium fission • 84 TeraJoules = 20 kton TNT
Bang! first H bomb test in 1952 • hydrogen fusion • 44 PetaJoules = 10 Mtons of TNT
unified atomic mass unit 1u is 1/12 of the mass of a carbon-12 atom mp = 1.007276u mn = 1.008665u me = 0.0005486u
Atoms are lighter than the nucleons which they are built from the mass defect, δis the difference between the total mass of the individual nucleons and the mass of the atomic nucleus mass defect of Helium mHe = 4.0026u
Binding energy binding energy of the nucleus is the energy needed to separate the nucleons
How much energy is released when a helium nucleus is formed? • mp = 1.00728u • mn = 1.00866 • mass of 42He nucleus = 4.00153u • 1u = 1.66054 x 10-27kg = 931.494MeVc-2
Atoms are lighter than the nucleons which they are built from the mass defect, δ mass from n and p energy released as nucleus is made Tsokos p.387qn1