1 dark matter increases density of Universe 1 density greater than critical

1 dark matter increases density of universe 1 density

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critical density is condition for flat Universe. (1) dark matter increases density of Universe. (1) density greater than critical density. (1) Universe will contract / big crunch. (1) [6] 11. any 4 from: end of H burning/red giant/supergiant (1) onset of He fusion/fusion of heavier nuclei (1) gravitational collapse of core (1) supernova explosion/ star explodes (1) suitable mass limit (chanderasekha limit 1.4M) (1) supported against gavity by neutron gas pressure/ ref to Fermi pressure (1) internal structure protons and electrons combined/ very thin atmosphere/ metallic crust (1) 4 [4] PhysicsAndMathsTutor.com 2
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12. (i) volume = 4 π (10,000) 3 /3 = 4.2 × 10 12 (1) density = 3.5 × 10 30 / 4.2 × 10 12 ecf (1) density = 8.4 × 10 17 kg/m 3 (1) 3 (ii) any two from density (very) much greater than material on Earth (1) quotes typical density on Earth 1 – 10 4 kg m –3 (1) atomic structure collapsed / density same as atomic nucleus (1) 2 [5] 13. (i) energies/temperatures irreproducible on Earth / laws of Physics break down (1) 1 (ii) temperature decreases (1) universe expanding/work done against attractive forces/ energy converted to mass (1) 2 (iii) any 3 from protons and electrons separate initially (1) matter-radiation equilibrium/charge prevents passage of em waves (1) proton-electron recombination /formation of atoms (1) gamma/ em waves no longer absorbed (1) 3 [6] 14. any 5 from: star-light shows red shift (1) galaxies (stars) receding from Earth (1) recessional velocity proportional to distance (1) cosmological microwave background radiation (CMBR) (1) uniform intensity in all directions (1) small ripple (1) (black body temperature) 2.7 K (3K) (1) High ratio of helium to hydrogen (1) Indicates very high temperatures existed (1) ratio too high to originate from stellar fusion (1) 5 [5] PhysicsAndMathsTutor.com 3
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matter-radiation equilibrium/charge prevents passage of em waves (1) proton-electron recombination /formation of atoms (1) gamma/ em waves no longer absorbed (1) 3 [6] 15. (i) H 0 = 75 / 3.1 × 10 19 (1) t 0 = 1 / H 0 = 4.13 × 10 17 s (1) t 0 = 4.13 × 10 17 s / 365 × 24 × 3600 = 1.3 × 10 10 y (1) 3 (ii)
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  • Spring '18
  • fatima
  • Big Bang, Cosmic microwave background radiation, Ambrose College

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