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22 Cards in this Set
- Front
- Back
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What are the assumptions of an Ideal Gas? Name 5 |
Large number of molecules moving in random directions, All collisions are perfectly elastic, total volume of molecules is negligible to volume of container, Duration of collisions is negligible, No inter molecular forces except during collisions |
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define Internal Energy for a gas |
the sum of the potential and kinetic energies of the molecules in a gas |
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What is the Internal Energy of an Ideal gas? |
the sum of the kinetic energies of the molecules, because potential energies are assumed to be zero. |
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Define Boyle's Law |
for a fixed mass of gas, the pressure is inversely proportional to the volume providing temp remains constant. |
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For a black body radiator, the frequency at which maximum radiation of energy occurs is proportional to ___________? |
Temperature. frequency is proportional to absolute temperature. λmaxT = 2.898e-3, so λ ∝ 1/T. f = 1/ λ therefore f ∝ T |
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Is kinetic energy conserved in a fission reactor? explain |
No, The KE gained by the particles is lost as heat in order to heat up the water to continue the generator. so because energy is lost through heat, KE is not conserved so the collisions are inelastic. |
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A mass-spring system oscillating at 3.0Hz on the surface of earth is moved to a region of space where the gravitational field strength is a third of that on the earths surface. what is it's new frequency? |
3.0Hz, the time period/frequency of a mass spring system is independent of the gravitational field strength. (varies with spring constant and mass) |
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Define a Forced Oscillation |
An oscillation in which external forces are regularly/periodically applied to the system in order to continue the oscillation |
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define a Free Oscillation |
An oscillation in which no external forces are applied following the initial displacement |
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Give 7 examples of background radiation sources. |
Living matter, Dead matter, Rocks (Radon gas), Food/drink, Cosmic Rays, Medical, Buildings |
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When a forced oscillation is damped, what can be said about the amplitude? |
The amplitude is reduced to a constantly lower value. (i.e amplitude remains the same with each oscillation but is lower than the undamped amplitude) |
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A sealed jar contains a mixture of different gasses, for a given temperature, what can be said about the mean kinetic energy of the molecules of each gas? |
They are the same temp, 1/2m=3/2kT so at a given temperature the mean kinetic energy of molecules will be the same (it is the mean square speed that varies with mass) |
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define Ionisation |
the process by which an atom becomes (+ or -) electrically charged through the gaining or loosing of electrons |
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define Isotope |
Two or more forms of the same element that have the same proton number, but a different amount of neutrons and hence a different mass number |
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explain why Alpha Particles have such a short range (and state this range) |
They have the greatest magnitude of charge out of the 3 radiation types, hence they easily ionise atoms as they pass by pulling electrons out of their shells. this takes away energy from the alpha particle because the electrons are gaining energy, quickly bringing it to rest. ounce at rest it gains electrons to become a helium atom. range is about a few cm in air |
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Explain the difference of origin of Gamma radiation and X-ray Radiation |
Gamma radiation occurs when there is a surplus of energy following alpha and/or beta decay. it is released from a nucleus in an excited state. X-rays are released from electrons falling down orbitals in an excited state but still gets rid of a surplus of energy. |
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A star with the same surface temperature as the sun but <1% of the suns luminosity can be described as what? |
A white dwarf |
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Describe the axes of a HR Diagram |
Y axis: luminosity, increasing in Powers of 10 as a multiple of the suns luminosity. X axis: absolute temperature, decreasing logarithmic scale |
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What can be said about the orbit of a satellite with a period of 24hrs? (name 3 things) |
Geosynchrous orbit, orbiting in the equatorial plane, same angular velocity as the earth |
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Why does a hot air balloon rise when heated? |
Heat causes air to expand, density of air decreases, upthrust increases so that U>mg hence it accelerates upwards |
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State the assumptions of boyles law |
Gas behaves as an ideal gas, Fixed mass of gas, constant temperature of gas |
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Why might carbon-11 be safe inside the body? |
Short half life, low ionisation |
