(A) Paper 2 exam style question wrongs

Question 1

What is the name of the first spacecraft that obtained images of the Moon’s far side?

Answer 1

Luna 3

Question 2

The Andromeda Galaxy is listed in the Messier Catalogue as M31.
Why did Charles Messier include the Andromeda Galaxy in his catalogue?

Answer 2

It appears as a fuzzy patch / is not starlike.
or: Because it is a galaxy.

Question 3

Explain how aurora are created

Answer 3

• Solar wind particles
• Deflected by Earth’s magnetic field/magnetosphere
• Excite atoms over the Earth’s poles (to produce light)

Question 4

Explain why the radio waves from a neutron star appear as pulses when received on Earth.

Answer 4

• Neutron star is spinning
• Radio waves are emitted from poles
• only Creating ‘lighthouse’ style
  rotating beam.

Question 5

State two reasons why liquid water is able to exist on the surface of the Earth.

Answer 5

• Sufficient gravity
• Temperature between 0oC and 100oC (Goldilocks’ Zone)
• Sufficient atmospheric pressure

Question 6

What type of star lies at the centre of a planetary nebula?

Answer 6

White dwarf

Question 7

What effect does an H-alpha filter have on most solar radiation?

Answer 7

The filter absorbs all but a narrow wavelength band of light from the Sun

Question 8

Explain why a H-alpha filter makes it possible to observe the Sun safely.

Answer 8

The intensity (1) of solar radiation passing through the telescope is reduced

Question 9

Explain whether the Sun would rotate through a greater or smaller angle than 120° in the same interval of time at a solar latitude of 60°N as compared to that of a solar latitude of 30N.

Answer 9

60°N is closer to the Sun’s equator therefore the Sun will rotate faster at this latitude. So in the same interval of time, the Sun will rotate through a greater angle than 120°.

Question 10

Which quantities are plotted on a Butterfly Diagram?

Answer 10

Sunspot latitude and time

Question 11

In order for thermonuclear fusion reactions to occur, the temperature must be high
enough.
Explain the reason for this.

Answer 11

• The particles taking part in thermonuclear fusion have similar/positive electric charges that mutually repel each other
• these particles/protons must be moving fast enough to overcome this (mutual force of) repulsion
• the temperature is a measure of the mean kinetic energy of the particles i.e. related to their typical speeds

Question 12

Which region of the sun has the smallest thickness?

Answer 12

Chromosphere

Question 13

What is the name of the Sun’s outer atmosphere?

Answer 13

Corona

Question 14

What is the main constituent of the inner Van Allen belt?

Answer 14

Electrons

Question 15

What is the main constituent of the outer Van Allen belt?

Answer 15

Protons

Question 16

The Earth’s magnetic field is caused by the motion of charged particles (electric currents) in one of its major divisions. In which major region do these charged particles flow?

Answer 16

Outer Core

Question 17

What makes the dust tail of a comet visible?

Answer 17

Reflection of sunlight

Question 18

Where do iron meteorites originate in?

Answer 18

The cores of asteroids

Question 19

A student suggests that ‘the distance from the Sun to the Kuiper Belt is an order of magnitude greater than from the Sun than the Asteroid Belt’. Do you agree with this student? Justify your answer:

Answer 19

Yes.
An ‘order of magnitude is a power of 10: multiplying the approximate distance of the Asteroid Belt from the Sun by 10 gives a result close to the distance between the
Kuiper Belt and the Sun

Question 20

Which photoreceptors in the human eye respond to bright lights?

Answer 20

Cones

Question 21

The main difference between a Galilean refractor and a Keplerian refractor is that the
Keplerian refractor…

Answer 21

consists of two convex lenses and not one

Question 22

Write a short account of how Saturn’s moon Enceladus is responsible for the planet’s
E-ring.

Answer 22

Water/ice is ejected from Enceladus’ geysers (1); some water/ice falls back onto
Enceladus and some is captured by the gravitational field of Saturn (1) forming its Ering.

Question 23

Most astronomers agree that the origin of the Moon was an impact between the Earth
and a Mars-sized body that occurred early in the Solar System.
State two further examples of large-scale collisions in the Solar System.

Answer 23

• orientations of Uranus (‘sideways’ spin)
• Venus (‘backwards’ spin);
• impact craters on the Moon, Mars, asteroids, - many planetary moons
• large iron core of Mercury.

Question 24

Explain why the likelihood that moons that come closer than planet’s Roche Limit are
likely to be broken apart only applies to moons that have a significantly large diameter.

Answer 24

• Tidal forces are gravitational in origin (1);
• gravitation follows an inverse square law (1);
• the moon must have a large enough diameter for the difference in gravitational pull on the ‘near’ and ‘far’ side of the moon to be significant/greater than elastic forces

Question 25

Explain briefly why the cores of the gas giant planets are significantly larger than those
of the terrestrial planets.

Answer 25

• For our Solar System, the Frost Line was about 5 AU from the Sun.
• Within the frost Line, volatile ices were unable to condense due to the high temperature (1)
• however, beyond the Frost Line, it was cold enough for ice to condense and these are thought to have caused the significantly larger cores of the gas giants

Question 26

There is very little hydrogen and helium gas in the inner Solar System, and yet the gas
giant planets have retained huge amounts of these gases in their atmospheres.
Suggest a likely reason for the absence of hydrogen and helium in the inner Solar
System.

Answer 26

Solar wind (1) is most likely reason for ‘blowing’ light gases (1); solar wind is ‘strongest’ closer to the Sun i.e. in the inner Solar System

Question 27

Which of the following opposing factors determines whether or not a planet or moon will have an atmosphere?

Answer 27

Thermal and gravitational

Question 28

Explain the connection between the dark absorption lines and the chemical
composition of the star.

Answer 28

• light passing through the outer layers a star is made of all wavelengths/energies (1)
• some of this light has the correct wavelength/energy to excite atoms in the star’s outer layers (1)
• when the atoms de-excite (1) they emit radiation/photons of the same wavelength/energy but in a random direction (1) and not necessarily ‘outwards’ (1)
• the wavelengths/energies at which these ‘reactions’ occur depends on the chemical element (1);
• light received on Earth is dimmer and so darker at these wavelengths (1).

Question 29

Explain how spectroscopy and the H-R diagram can determine distances to stars

Answer 29

• obtain spectrum of star and determine spectral class
• interpolate (readoff) the absolute magnitude (assuming the star is on the main sequence)
• observe the star to determine its apparent magnitude (1)
• use the distance modulus equation to calculate d

Question 30

In which region of the electromagnetic spectrum were quasars first discovered?

Answer 30

X rays

Question 31

Using the terms primary star and secondary star, explain the cause of the variability
in an eclipsing binary star.

Answer 31

• for most of the time, the primary and secondary stars are not aligned
• this gives rise to the ‘constant’ brightness
• the larger/primary ‘dip’ occurs when the
  dimmer/secondary star is directly in front of the brighter/primary star
• the smaller/secondary ‘dip’ occurs when the secondary star is behind the primary star

Question 32

Which type of variable star is used by astronomers to determine distances to stars?

Answer 32

Cepheid variable

Question 33

Give two major discoveries made by astronomers using radio waves.

Answer 33

• quasars
• pulsars
• radio galaxies
• jets from black holes
• protoplanetary discs,
• structure and rotation of the Milky Way

Question 34

Explain why the aperture of a radio telescope should be as large as possible

Answer 34

• this is to achieve the maximum possible resolution (amount of detail) (1).
• This is due to the wavelengths of radio waves being large
• resolution depends inversely on wavelength - large aperture size compensates for large wavelength of radio waves

Question 35

Explain what is meant by averted vision.

Answer 35

• averted vision means looking slightly to the side
• of a faint extended object so that light falls onto the rods (not the cones)
• of the eye’s retina; in dark conditions, the cones (which lie where the optical axis joins the retina)
• are not sensitised, but the rods (which lie adjacent to the optical axis are

Question 36

Which two nebulae occur before main sequence stars are formed?

Answer 36

Emission and absorption nebulae

Question 37

What might initiate the collapse of a giant gas cloud that may eventually form stars?

Answer 37

Supernova and gravitational waves

Question 38

In which region of a spiral galaxy does star formation occur?

Answer 38

Spiral arms

Question 39

Main sequence stars towards the bottom right of the H-R diagram are

Answer 39

Old and dim

Question 40

The location of a star on the main sequence is determined by its

Answer 40

Mass

Question 41

Main sequence stars towards the top left of the H-R diagram are

Answer 41

Young and bright

Question 42

Suggest why neutron stars and black holes are not found on the H-R diagram

Answer 42

Neither emits enough radiation to be ‘bright’ enough to register on the luminosity/absolute magnitude/vertical axis

Question 43

Explain why it is not possible to study the structure and rotation of our Galaxy using
visible light.

Answer 43

Visible light is unable to penetrate/pass through dust in the spiral arms.

Question 44

Active galaxies are so-called because

Answer 44

they emit large quantities of non-thermal radiation

Question 45

Explain why the unit of the Hubble constant can be given as an inverse of time such as
the ‘per second’.

Answer 45

The basic unit is the kilometre per second per megaparsec. The kilometre and
megaparsec are both units of distance/length (1); these can effectively cancel (1) to
leave the unit as the ‘per second’

Question 46

The value of the Hubble constant can be found by determining the

Answer 46

gradient of a velocity - distance graph

Question 47

Describe briefly how astronomers obtained Hubble Deep Field images

Answer 47

The Hubble Space Telescope/HST obtained out long-exposure images of (apparently) ‘empty space’