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FM Chem 11 > P8 - Physics on the move > Flashcards

P8 - Physics on the move Flashcards

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1
Q

How long ago was the big bang?

A

13.8 billion years ago

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2
Q

What happens when a light source moves away from you?

A
  • Red shift: The wavelength of light that is emitted INCREASES, DECREASING the frequency.
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3
Q

What happens when a light source moves toward you?

A
  • Blue shift: The wavelength of light that is emitted DECREASES, INCREASING the frequency.
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4
Q

What is the Big Bang Model?

A
  • Scientists believe the universe started from the initial singularity, a point extremely dense and smaller than the size of an atom, which contained all the energy and matter in the universe.
  • This then suddenly expanded 13.7 billion years ago.
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5
Q

Evidence for the Big Bang

A
  • In the 1960s scientists discovered that there was microwaves radiation coming from all direction, which was radiation left over from the Big Bang.
  • This is called “Cosmic Microwave Background Radiation” (CMBR).
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6
Q

Define Planets

A

Object that are spherical because of gravity, that orbit around the sun.

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7
Q

Define Comets

A

Objects made of ice and dust in orbit around the sun, usually with very long, thin orbits (elliptical, often travel near the end of the solar system).

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8
Q

Order of planets in the solar system

A
  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
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9
Q

Asteroid belt

A
  • In between Mars and Jupiter, there is an asteroid belt, which is a cluster of asteroids.
  • Asteroids are pieces of rock left over from the formation of the solar system.
  • They contain a dwarf planet called Ceres.
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10
Q

How was the Sun formed? What is it made of?

A
  • The Sun is a huge cloud of dust and hydrogen gas.
  • Gravity pulled the dust and hydrogen gas together, making the central core very hot.
  • Eventually, particles were hot enough for nuclear fusion to occur.
  • There is a balance between the gravitational attraction inward and the expansion of hot gases outward.
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11
Q

What are asteroids made of?

A

Mainly rock and metals.

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12
Q

Define Nebula

A
  • Giant cloud of dust and gas in space.
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13
Q

Describe the formation of protostars.

A
  • Over time, the force of gravity in a nebula pulls the dust and gas together, to form a protostar.
  • As more and more particles collide and join the protostar, it gets bigger and bigger, making the force of gravity stronger.
  • The gravity also squeezes the protostar, making it more dense.
  • This means particles insides a protostar collide more and raises their temperature.
  • When the temperature and pressure is high enough, nuclear fusion can occur, releasing massive amounts of energy.
  • At this point, we call something a ‘main-sequence star’.
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14
Q

What stage is our sun currently in (life cycle of stars)

A
  • The sun is currently a main-sequence star.
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15
Q

What happens at the end of the main-sequence?

A
  • Stars runs out of fuel, nuclear fusion stops.
  • Force of gravity makes the star collapse.
  • This then increases pressure and temperature, inducing fusion.
  • Star expands again, forming a Red Giant or Red Super Giant.
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16
Q

What factor determines how much a star expands at the end of the main-sequence?

A
  • The size of the star
  • Small/Medium Stars: Red Giant
  • Large Stars: Red Super Giant
17
Q

What happens after a red giant is formed?

A
  • Eventually, it becomes unstable, and expels it outer layers of dust & gas.
  • It leaves behind a ‘white dwarf’, a hot and dense solid core that doesn’t do any fusion.
18
Q

What’s the reason behind the name ‘White Dwarf’?

A
  • The emit lots of life.
  • They are very small.
19
Q

What happens after a white dwarf is formed?

A
  • Over time, the white dwarfs gets cooler and darker, as it emits all its energy.
  • It transitions into a black dwarf, as it no longer has enough energy to emit light and so becomes dark.
20
Q

What happens after a red super giant is formed?

A
  • Red Super Giants began to shine brighter, as they undergo more nuclear fusion.
  • After several cycles of contraction, and expansion, they eventually explode in a supernova.
  • A supernova forms elements heavier than iron that are ejected into the universe.
21
Q

What happens after a supernova?

A
  • Very large stars condense into an ultra-dense core, called a neutron star.
  • Incredibly massive stars collapse completely to form a black hole.
22
Q

Geostationary Orbit Satellites

A
  • 24 hours for one orbit
  • 36,000km above the Earth’s surface
  • Remains in a fixed position above the Earth’s equator
  • Used for satellite television, communications
23
Q

Polar Orbit Satellites

A
  • 2 hours for one orbit
  • 2000km above the Earth’s surface
  • Orbits of the Earth’s poles
  • Used for weather, military (spying), observation of the Earth
24
Q

Describe P waves

A
  • Longitudinal waves
  • They can pass through solids and liquids
  • Travel faster than S waves
25
Q

Describe S waves

A
  • Transverse waves
  • Can ONLY travel through solids
  • Travel in curved paths, due to density changes in the Earth.
26
Q

What equipment measures seismic waves?

A
  • Seismometers
27
Q

Describe where & why S waves can/cannot be detected

A
  • The S-wave shadow zone (usually on the other side of the world opposite the core).
  • This is because S waves cannot pass through a liquid, so the Earth must contain a liquid core.
28
Q

Describe where & why P waves can/cannot be detected

A
  • P wave shadow zones.
  • This is because P waves travel faster in solids than in liquids.
  • So, the P waves slow down when they enter the liquid outer core.
  • This makes them refract, when they enter/leave the outer core.
  • This also confirms the outer core is a liquid.
  • Faint P waves can be detected in the P wave shadow zone, so the earth contains a solid inner core.
29
Q

How do we know the earth has a liquid outer core, and a solid inner core?

A
  • S-waves cannot travel through the outer core, so it must be a liquid.
  • Faint P waves can be detected in the P wave shadow zone, so the earth must contain a solid inner core.
  • P waves refract when they enter/leave the outer core, so the outer core is a liquid.
30
Q

What is the voltage and frequency of mains power (domestic supply)?

A

230V
50Hz

31
Q

What are three different wires in an appliance, and their colours/uses?

A
  • Live wire (brown)
  • Neutral wire (blue)
  • Earth wire (green and yellow)
  • Live & Neutral wire make a complete circuit.
  • Earth wire is not connected to mains, it’s connected to the ‘Earth’, which is usually a large metal pole buried in the ground.
32
Q

Safety features in metal casing

A
  • If the live wire becomes loose, it can touch metal casing, and make it ‘live’.
  • To stop this from happening, the earth wire connects the case to the pole so current flows to the Earth through the wire, not you.
  • Casing can be made of plastic so no current flows. These appliances are ‘double insulated’.
  • Fuses are used, so they melt to switch off the current.
33
Q

Biofuels

A

Renewable fuels that come from living material, such as wood, ethanol, sugar, or methane (from sewage).

34
Q

Sources of non-renewable energy

A
  • The Sun (solar energy)
  • Tides
  • Wind
  • Hot rocks beneath the ground (geothermal energy)
  • Water high up, such as behind dams. (hydroelectric)
35
Q

SI units for joule (joule - petajoule)

A
  • Power of 1: Joule
  • Power of 3: Kilo-
  • Power of 6: Mega-
  • Power of 9: Giga-
  • Power of 12: Tera-
  • Power of 15: Peta-
36
Q

SI units for joule (joule - femtojoule)

A
  • Power of -3: Milli-
  • Power of -6: Micro-
  • Power of -9: Nano-
  • Power of -12: Pico-
  • Power of -15: Femto-
37
Q

What do individuals/governments consider when deciding about which energy sources to use?

A
  • Cost: Setting up, removing, maintaining
  • Effect on environment: Pollution, how it looks for locals
  • Contribution to climate change
  • How long the sources last (sustainability)
38
Q

Describe the use of transformers in the national grid

A
  • Step-up transformers increase the p.d to nearly 400,000V reduce heating effect (energy lost by heat), making the distribution of electricity more efficient.
  • Step-down transformers decrease the voltage to 230V for use in home.

FM Chem 11 (12 decks)

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