IGCSE Physics 0625 — Topic 6: Space Physics

Question 1

What causes day and night on Earth?

AThe Earth's orbit around the Sun BThe rotation of the Earth on its axis CThe tilt of the Earth's axis DThe Moon blocking sunlight

Question 2

The Earth takes approximately 365.25 days to orbit the Sun. What phenomenon does this orbital period primarily explain?

AThe cycle of day and night BThe cycle of the seasons CThe phases of the Moon DThe occurrence of tides

Question 3

During a new Moon, an observer at Greenwich Royal Observatory would see:

AThe entire face of the Moon illuminated BThe left half of the Moon illuminated CNo visible Moon in the night sky DThe right half of the Moon illuminated

Question 4

A satellite orbits the Earth at a radius of 7000 km with an orbital period of 5800 s. Using v = 2πr/T, what is the orbital speed?

A5.4 km/s B7.6 km/s C9.8 km/s D11.2 km/s

Question 5

When it is summer in the United Kingdom, it is winter in:

ASpain BCanada CAustralia DJapan

Question 6

The Moon takes approximately 28 days to orbit the Earth. Which sequence correctly shows the Moon phases?

ANew Moon → First Quarter → Full Moon → Last Quarter BFull Moon → First Quarter → New Moon → Last Quarter CNew Moon → Last Quarter → Full Moon → First Quarter DFull Moon → Last Quarter → New Moon → First Quarter

Question 7

An asteroid orbits the Sun at an average radius of 3.0 × 10¹¹ m with a period of 2.0 × 10&sup7; s. What is its orbital speed?

A47 m/s B4700 m/s C9.4 × 10⁴ m/s D9.4 × 10⁷ m/s

Question 8

Which list shows the planets in the correct order from the Sun?

AMercury, Venus, Earth, Mars, Saturn, Jupiter, Uranus, Neptune BMercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune CMercury, Mars, Venus, Earth, Jupiter, Saturn, Neptune, Uranus DVenus, Mercury, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Question 9

The inner planets (Mercury, Venus, Earth, Mars) are described as rocky planets. What distinguishes them from the outer planets?

AThey have no moons BThey are composed mainly of rock and metal with solid surfaces CThey orbit faster than the speed of light DThey are larger than the outer planets

Question 10

According to the accretion model, how did the Solar System form?

AThe Sun captured passing planets from another star system BA cloud of gas and dust collapsed under gravity, forming a spinning disc from which planets formed CThe planets were ejected from the Sun during a massive explosion DDark matter condensed to form the planets directly

Question 11

The Sun is approximately 1.5 × 10¹¹ m from Earth. How long does light take to travel from the Sun to Earth? (c = 3.0 × 10⁸ m/s)

A50 s B500 s C5000 s D50 000 s

Question 12

Jupiter orbits at approximately 7.8 × 10¹¹ m from the Sun. How long does light take to reach Jupiter from the Sun?

A260 s B2600 s C26 000 s D260 000 s

Question 13

Planets orbit the Sun in elliptical paths. At which point in its orbit does a planet move fastest?

AAt its farthest point from the Sun (aphelion) BAt its closest point to the Sun (perihelion) CAt the midpoint of its orbit DIts speed remains constant throughout

Question 14

Which planet has the shortest orbital period?

AVenus BMercury CMars DEarth

Question 15

The gravitational field strength on the surface of Mars is about 3.7 N/kg, compared to 9.8 N/kg on Earth. A 60 kg astronaut would weigh approximately what on Mars?

A22 N B60 N C222 N D588 N

Question 16

Which statement about the orbits of planets in our Solar System is correct?

AAll planets orbit the Sun in perfect circles BAll planets orbit the Sun in ellipses with the Sun at one focus CInner planets orbit in circles while outer planets orbit in ellipses DAll planets orbit at the same speed

Question 17

The Sun is classified as a:

ARed giant star BWhite dwarf star CMedium-sized main sequence star DNeutron star

Question 18

What are the two most abundant elements in the Sun?

AOxygen and carbon BHydrogen and helium CIron and nickel DNitrogen and oxygen

Question 19

The Sun emits radiation across a range of wavelengths. Which types of radiation does it primarily emit?

AX-rays, gamma rays, and radio waves BInfrared, visible light, and ultraviolet COnly visible light DOnly ultraviolet radiation

Question 20

What process produces energy in the core of the Sun?

ANuclear fission of uranium atoms BChemical combustion of hydrogen gas CNuclear fusion of hydrogen into helium DRadioactive decay of heavy elements

Question 21

The temperature at the Sun's core is approximately:

A6000 °C B100 000 °C C1 000 000 °C D15 000 000 °C

Question 22

What is a galaxy?

AA single large star surrounded by planets BA collection of billions of stars held together by gravity CA cloud of gas where stars are forming DThe empty space between stars

Question 23

The Milky Way is:

AA planet in our Solar System BA nebula where new stars form CThe galaxy that contains our Solar System DThe nearest star to our Sun

Question 24

One light-year is defined as:

AThe distance light travels in one year, approximately 9.5 × 10¹⁵ m BThe time it takes light to travel one metre CThe distance from the Earth to the Sun DThe distance from the Earth to the nearest star

Question 25

The nearest star to our Sun, Proxima Centauri, is about 4.0 × 10¹⁶ m away. How many light-years is this? (1 ly = 9.5 × 10¹⁵ m)

A0.42 ly B4.2 ly C42 ly D420 ly

Question 26

A star like our Sun will eventually become a:

ABlack hole BNeutron star CWhite dwarf DSupergiant

Question 27

What is the correct life cycle for a star much more massive than the Sun?

AProtostar → Main sequence → Red giant → White dwarf BProtostar → Main sequence → Red supergiant → Supernova → Neutron star or black hole CProtostar → Red giant → Main sequence → Supernova DMain sequence → Protostar → Supergiant → White dwarf

Question 28

A protostar forms when:

AA white dwarf explodes BA cloud of gas and dust collapses under gravity CTwo neutron stars collide DA main sequence star runs out of hydrogen

Question 29

The Lovell Telescope at Jodrell Bank Observatory near Manchester detects radio waves from distant galaxies. Radio telescopes can observe objects that optical telescopes cannot because:

ARadio waves are faster than light BRadio waves can pass through dust clouds that block visible light CRadio waves are brighter than visible light DRadio telescopes are always larger than optical telescopes

Question 30

Which statement correctly describes the fate of a red giant star similar to our Sun?

AIt explodes as a supernova, leaving a neutron star BIt collapses directly into a black hole CIt sheds its outer layers as a planetary nebula, leaving a white dwarf DIt returns to being a main sequence star

Question 31

The estimated diameter of the Milky Way galaxy is approximately:

A1000 light-years B10 000 light-years C100 000 light-years D1 000 000 light-years

Question 32

When astronomers observe light from distant galaxies, they notice that spectral lines are shifted towards the red end of the spectrum. This is called:

ABlueshift BRedshift CBlackbody radiation DDiffraction

Question 33

What does the redshift of distant galaxies provide evidence for?

AThe Universe is contracting BThe Universe is expanding CThe Universe is static and unchanging DGalaxies are moving towards us

Question 34

The Big Bang theory states that:

AThe Universe has existed forever in its current state BThe Universe began from a very small, hot, dense state and has been expanding ever since CThe Universe was created when two galaxies collided DThe Universe expands and contracts in a repeating cycle

Question 35

Cosmic microwave background radiation (CMBR) is:

ARadiation produced by mobile phone masts BRadiation from the Sun reflected by cosmic dust CLow-frequency radiation detected uniformly from all directions in space, left over from the early Universe DX-rays produced by black holes

Question 36

A galaxy is moving away from Earth at 1.5 × 10⁶ m/s and is 6.8 × 10²³ m away. Using H₀ = v/d, calculate the Hubble constant.

A2.2 × 10⁻¹⁸ s⁻¹ B4.5 × 10⁻¹⁸ s⁻¹ C2.2 × 10⁻¹⁷ s⁻¹ D4.5 × 10⁻¹⁷ s⁻¹

Question 37

Using H₀ = 2.2 × 10⁻¹⁸ s⁻¹, the estimated age of the Universe is:

A4.5 × 10⁹ years B1.4 × 10¹⁰ years C2.2 × 10¹⁸ years D4.5 × 10¹⁷ years

Question 38

Galaxy A has a redshift twice as large as Galaxy B. According to Hubble's law, this means Galaxy A is:

ATwice as bright as Galaxy B BHalf as far away as Galaxy B CTwice as far away as Galaxy B DThe same distance as Galaxy B but moving faster

Question 39

Which two pieces of evidence most strongly support the Big Bang theory?

AThe existence of black holes and neutron stars BThe redshift of distant galaxies and cosmic microwave background radiation CThe existence of planets and the Moon's phases DSolar flares and the aurora borealis

Question 40

A galaxy is at a distance of 2.0 × 10²² m from Earth. Using H₀ = 2.2 × 10⁻¹⁸ s⁻¹, what is its recession speed?

A4.4 × 10⁴ m/s B9.1 × 10³⁹ m/s C4.4 × 10⁴⁰ m/s D9.1 × 10⁻⁴⁰ m/s

Paper 2 — Multiple Choice

Section A — The Earth

Section B — The Solar System

Section C — The Sun as a Star

Section D — Stars

Section E — The Universe