Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics P5-P8 > P8.3 New > Flashcards

P8.3 New Flashcards

8.3.1 - 8.3.3 done, Add .4 and .5, then need to check p5.1

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Define the Doppler effect

A

The physical phenomena by which there is a change in the observed frequency/wavelength of wave, due to relative motion between observer and source.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 examples of relative motion

A

source moving
OR observer moving
OR BOTH source AND observer moving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The Doppler effect with sound waves.

When the sound source moves towards you…

A

When the sound source moves towards you…

… wave peaks move closer together…

… wavelength gets smaller…

… frequency/pitch of sound increases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The Doppler effect with sound waves.

When the sound source moves away from you…

A

When the sound source moves away from you…

… wave peaks move further apart…

… wavelength gets bigger…

… frequency/pitch of sound decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Unlike sound, Doppler effect with light waves is very difficult to observe.

Why?
So when’s it observed?

A

This is because light waves have a much smaller wavelength than sound waves

Doppler effect is observed when the relative motion between observer and source is very large…

… is observed for distant stars as they are moving very fast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Red shift

  • what?
  • what it implies?
A

The shift in wavelength of the light from distant stars/galaxiesto longer wavelengths.

Implies that distant galaxies/stars are moving away from us

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Blue shift

  • what?
  • what it implies?
A

The shift in wavelength of the light from distant stars/galaxiesto shorter wavelengths.

Implies that distant galaxies/stars are moving towards us

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how is red shift linked to the big-bang model?

A
  • light from distant galaxies is red shifted
    so galaxies are moving away from us
  • and so if all galaxies are moving away from each other, at one point all matter must have existed at a single point in space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a spectrum

A

A spectrum is the range of wavelengths (colours)observed when light from a source is separatedinto its separate wavelengths.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Steady state theory

A

Up until 1965, a lot of scientists believed theSteady State Theory to correctly explain the expanding universe as seen by the red-shift. “The universe just came into existence… and then started expanding”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

CMBR stands for

A

cosmic microwave background radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Tell about cosmic microwave background radiation

A

At the beginning of the universe, all the energy of the universe would have manifested as very short wavelength gamma waves.

As the universe expanded, this gamma radiation would have stretched out to longer and longer wavelengths… and is nowMICROWAVE RADIATION.

The fact that these microwaves uniformly/evenly fill the universe suggests they all started off from a single point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does Cosmic Microwave Background Radiation provide evidence for The Big Bang Theory? (6)

A

The Big Bang Theory states that all the matter and energy of the universe was concentrated at a single point.

At the start of the universe, this energy was high energy gamma radiation.

Since the universe has been expanding, these gamma waves have stretched out.

They are now seen as longer wavelength microwaves.

And are seen uniformly in all directions in the universe…

… implying they all must have started at the same point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The solar system composition - 5

A

The SunStar at the centre of the solar system.

PlanetsSpherical bodies that orbit the Sun.

MoonsSpherical bodies that orbit planets.

Minor PlanetsSmall spherical objects that orbit the Sun.

Comets
Dust/ice that orbit the Sun with long period, elliptical orbits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Inner planets

  • 4 examples
  • fact about them
  • 2 key details
A
  • mercury, Venus, earth, mars
  • rocky, have an atmosphere
  • Mercury atmosphere very thin .. Venus is hotter despite being further away from sun
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Outer planets

  • 4 examples
  • 3 facts
A
  • Jupiter, Saturn, Uranus, Neptune

- gas giants / ice giants ; rings and lots of moons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Asteroid belt

  • what
  • where
A
  • Pieces of rock left over from the formation of the Solar System;
  • between Jupiter and Mars.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Formation of the solar system - part 1 (steps to a prostar)

A
  • The Sun and the rest of our Solar System were formed from the remains of a supernova.
  • Clouds of dust and gas were pulled together by the force of gravity.
  • When enough gas and dust had gathered and became dense enough to start nuclear fusion, a protostar is formed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Formation of the solar system - part 2 (to do with the prostar)

A

As protostar becomes denser and hotter
…… particles speed up
… particles collide more energetically
… nuclear fusion begins, forming a main sequence star.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Life cycle of stars - beginning

  • same/similar/different for stars ?
  • what happens?
A
  • same beginning for all stars
  • Dust and gas gather under gravity to form a protostar.
  • Once the protostar has become hot and dense enough,nuclear fusion begins and the star becomes amain sequence star.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Life cycle of stars - middle

  • same/similar/different for stars ?
  • what happens?
A
  • similar middle for all stars

A star is stable during its main sequence.
—>Radiation pressure outwards from nuclear fusion balances gravitational attraction inwards
—> equilibrium / stability

Eventually the hydrogen nuclei will run out.

  • star cools, radiation pressure drops
  • gravitational force collapses star, causing it toheat up again
  • fusion of heavier elements begins
    … energy from fusion increases… radiation pressure increases
    … star expands outwards… becoming either a RED GIANT or a RED SUPER GIANT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Life cycle of stars - Ending

  • same/similar/different for stars ?
A

Different ENDING depending upon MASS OF STAR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Life cycle of stars - ending

- small star what happens

A

Nuclei for fusion run out

 fusion slows down
 radiation pressure decreases
 gravitational force collapses star

 heats up, becomes white dwarf

 eventually cools down to form black dwarf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Life cycle of stars - ending

- large star what happens

A

Lots of heavier nuclei fused together torelease lots of energy

 large increase in radiation pressure outwards
 much larger than gravitational pull inwards
 star explodes in a supernova
 very dense neutron star forms
 if neutron star is very dense, considered a black hole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Low mass star life cycle

A

Protostar, main sequence star, red giant, white dwarf, black dwarf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

high mass star life cycle

A

Protostar, main sequence star, ref giant, supernova, neutron star, (if lots of mass…) black hole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Compare inner + outer planets

A

Inner = mostly rocky

Outer = mostly gas

Inner = small mass, small gravitational fields, few moons

Outer = large mass, large gravitational fields, many moons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How was the sun formed? - textbook (4)

A
  • like other planets, formed from a huge cloud of dust and hydrogen gas
  • Gravity pulled the gas and dust together, and as that happened the central core got very hot
  • Eventually, particles were moving fast enough for nuclear fusion to start
  • Now there is a balance between the gravitational attraction inwards and the expansion of the very hot gases outwards
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Life cycle of stars - beginning

  • same/similar/different for stars ?
  • what happens?
A
  • same beginning for all stars
  • Dust and gas gather under gravity to form a protostar.
  • Once the protostar has become hot and dense enough,nuclear fusion begins and the star becomes amain sequence star.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Life cycle of stars - middle

  • same/similar/different for stars ?
  • what happens?
A
  • similar middle for all stars

A star is stable during its main sequence.
—>Radiation pressure outwards from nuclear fusion balances gravitational attraction inwards
—> equilibrium / stability

Eventually the hydrogen nuclei will run out.

  • star cools, radiation pressure drops
  • gravitational force collapses star, causing it toheat up again
  • fusion of heavier elements begins
    … energy from fusion increases… radiation pressure increases
    … star expands outwards… becoming either a RED GIANT or a RED SUPER GIANT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Life cycle of stars - endinf

  • same/similar/different for stars ?
A

Different ENDING depending upon MASS OF STAR

32
Q

Life cycle of stars - ending

- small star what happens

A

Nuclei for fusion run out

 fusion slows down
 radiation pressure decreases
 gravitational force collapses star

 heats up, becomes white dwarf

 eventually cools down to form black dwarf

33
Q

Life cycle of stars - ending

- large star what happens

A

Lots of heavier nuclei fused together torelease lots of energy

 large increase in radiation pressure outwards
 much larger than gravitational pull inwards
 star explodes in a supernova
 very dense neutron star forms
 if neutron star is very dense, considered a black hole

34
Q

Low mass star life cycle

A

Protostar, main sequence star, red giant, white dwarf, black dwarf

35
Q

high mass star life cycle

A

Protostar, main sequence star, ref giant, supernova, neutron star, (if lots of mass…) black hole

36
Q

Compare inner + outer planets

A

Inner = mostly rocky

Outer = mostly gas

Inner = small mass, small gravitational fields, few moons

Outer = large mass, large gravitational fields, many moons

37
Q

What’s a satellite?

A

A satellite is any body that orbits a planet or star.

38
Q

2 types of satellites w/examples

A

Natural SatellitesThe moon is a satellite of Earth.Earth is a satellite of the Sun.

Artificial SatellitesCommunications Satellites in orbit about Earth.

39
Q

2 types of orbit

A
  • geostationary orbit

- (low) polar orbit

40
Q

Geostationary orbit

  • time for one orbit
  • height above Earth’s surface (km)
  • features
  • uses (2)
A

-Orbital Time Period = 24 Hours
Orbital Height = about 36,000km
Launched above equator.∴ satellite remains in a fixed position relative to the Earth

Communications/GPS, satellite television(why satellite dishes down a road face the same way)

41
Q

Polar orbit

  • time for one orbit
  • height above Earth’s surface (km)
  • features
  • uses (3)
A

Orbital Time Period = 2 Hours
Orbital Height = up to 2000km
Launched about poles.∴ satellite rotates about the Earth once every 2 hours, as Earth rotates under it… satellite scans entire surface of Earth, very quickly.

  • military (spying)
  • observation of Earth
  • weather
42
Q

In order to get the correct TIME PERIOD for a satellite,you must get correct __ __ for the satellite.In order to get the correct __ __,you must get correct the satellite __ __.

A

In order to get the correct TIME PERIOD for a satellite,you must get correct ORBIT RADIUS for the satellite.In order to get the correct ORBIT RADIUS,you must get correct the satellite ORBIT VELOCITY.

43
Q

I.e. - last card - to get correct time period

A

The velocity you launch a satellite at (in its orbit… not on the way up to space!) will determine the radius the satellite orbits the Earth at, and the time period of orbit.High Velocity = Small Orbit Radius = Small Time Period(A-level Physics)

44
Q

Satellite OrbitsElliptical vs Circular Orbits

[Natural Satellites]

A
  • Almost all planets orbit their star in an elliptical orbit.
  • An elliptical orbit differs from a circular one in that its radius isn’t fixed.
  • However, at any given point in the orbit, we can treat the planet as moving in a circular orbit of a given radius.
45
Q

Tell about force on satellite in orbit (4)

A
  • A body in a circular orbit is constantly accelerating, as the direction of its velocity is constantly changing.
  • Hence, a resultant force must be acting upon a planet orbiting its star.
  • A resultant force that causes a body to performcircular motion is known as the centripetal force.(A-Level Physics)
  • The centripetal force for a planet is provided by the gravitational attraction of its star.
46
Q

Centripetal force

  • where it acts
  • how it acts
  • therefore
A
  • The centripetal force/gravitational attractionalways acts towards the centre of the circular motion/orbit.
  • The centripetal force on any bodyalways acts perpendicular to the body’s velocity.
  • Therefore, the speed of the body never changes!(just the direction)
47
Q

Stable orbits

  • what is it
  • too slow?
  • too fast?
  • further away = ?
A
  • A stable orbit maintains a constant radiusabout the body its orbiting.
  • If a satellite moves too slow…… gravitational attraction will pull it in.
  • If a satellite moves too fast…… gravitational attraction is not great enough to hold onto the body and it flies away.
  • The further away a body is from the body it orbits, the slower its velocity needs to be to maintain a stable orbit…… the longer its time period.
48
Q

Temp =

A

A measure of the average kinetic energy of particles of a system

49
Q

Greater temp = greater __ = (3)

A

Kinetic energy,

  • faster particles displace
  • faster particles rotate
  • faster particles vibrate
50
Q

when charged particles vibrate ?

A

Emit EM waves

51
Q

The faster charged particles vibrate?

A

The higher the frequency of emitted EM radiation

52
Q

Explain the different colours of hot objects

A
  • greater temp. of a body..
  • the faster the particles vibrate
  • EM waves of greater frequency emitted
  • therefore bodies that glow blue (high frequency) are hotter than those that glow red (low frequency)
53
Q

Blue or red object hotter?

Why?

A

bodies that glow blue (high frequency) are hotter than those that glow red (low frequency)

54
Q

How temp increases/decreases

A

If a body absorbs more radiation than it emits, its temperature will increase.

If a body emits more radiation than it absorbs, its temperature will decrease.

55
Q

PIC

Higher frequency of radiation = ?

A

The hotter the body, the higher the frequency of radiation it emits.

56
Q

Explain why hitters stars emit blue light rather than red light (3)

A

Hotter stars have a higher temperature.

Thus, the particles of a hotter star are vibrating faster.

Charged particles that vibrate faster will emit EM radiation of a higher frequency (blue as opposed to red).

57
Q

Layers of the earth from outside to inside

A

Crust/mantle —> outer core —> inner core

58
Q

State of earth from outside to inside

A

The crust is a solid layer of rock about 50km thick.

The crust surrounds a thicker layer of molten (liquid but dense like a solid) rock, called the mantle. - ‘solid but can flow’

The Earth has a solid inner core and a liquid outer core, beneath the mantle.

(Solid —> liquid —> solid)

59
Q

Nice PIC of the Earth’s structure

A

.

60
Q

The study of the Earth

A

Seismology

61
Q

Tell us about seismic waves - how created,

2

A
  • An earthquake occurs when forces inside the Earth become large enough to break and move layers of rock.
  • The energy transferred during an Earthquake
    creates shockwaves, Seismic Waves.
62
Q

How seismic waves travel

A

Seismic waves travel through the Earth andacross the surface of the Earth.

63
Q

Studying seismic waves has led to what ?

A

Studying Seismic waves is what has led to information about the structure of the Earth.

64
Q

Earthquakes originate (where?).

The point where the Seismic Wave originates, is called (what?).

The epicentre of the earthquake. (Is what?)

A

Earthquakes originate in the Earth’s crust.

The point where the Seismic Wave originates, is called the focus.

The nearest point on the surface to the focus, is known as the epicentre of the earthquake.

65
Q

How are earthquakes recorded

A

Earthquakes are recorded by detectors on the surface of the Earth, known as seismometers.

66
Q

2 different ropes of seismic waves

A 
Primary waves (P waves)
Secondary waves (S waves)
67
Q

Describe primary waves (3)

A
  • Cause initial tremors lasting about 10 minutes.
  • Longitudinal waves that push and pull the Earth.
  • Can travel through solids and liquids.
68
Q

Describe secondary waves (3)

A
  • More tremors a few minutes later.
  • Transverse waves that shake up and down the Earth.
  • Cannot travel through liquids.
69
Q

PIC

Describe and explain how P-waves and S-waves can be used to deduce the structure of the Earth.

  • 1 - crust
A

P and S waves refract/bend slowly as they travel through the solid crust.

(∵ the density of the crust slowly changes as you travel further into the Earth)

70
Q

Describe and explain how P-waves and S-waves can be used to deduce the structure of the Earth.

  • 2 - mantle and outer core
A

At the boundary between the mantle and the outer core, the P and S waves refract a lot, because their speed suddenly changes a lot.

(∵ there is a large difference in density between solid mantle and liquid outer core)

71
Q

S WAVES

- 3 - liquid core

A

S waves cannot travel through the liquid core, so are not detected on the other side of the Earth, producing S-wave shadow zones.

72
Q

P WAVES

- 4 - mantle/outer core

A

P waves are refracted a lot as they cross the mantle/outer core boundary, also creating regions where they are not detected, producing P-wave shadow zones.

73
Q

Describe and explain how P-waves and S-waves can be used to deduce the structure of the Earth.

5 - existence of shadow zones

A

The existence of these shadow zones has led scientists to form the current model of the inside of the Earth.

74
Q

Ex[lain how seismic waves detected around the world show that part of the Earth is liquid (6)

A

P-waves are longitudinal and can travel through solids and liquids.

S-waves are transverse and can only travel through solids.

Following an earthquake, P-waves are detected on the other side of the Earth, but S-waves are not detected.

This implies S-waves were unable to pass through part of the Earth.

Part of the Earth must therefore be liquid.

75
Q

The path of the waves in the mantle are curved

A) explain why
B) suggest what this tells you about the mantle

A

A) The waves refract/bend as they travel through the Earth.

B) The Earth contains layers of different densities, such that boundaries between media exist, giving rise to refraction.[recall that just like reflection and diffraction, refraction is a wave phenomenon that only when waves cross the boundary between media]

Physics P5-P8 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions