IGCSE Physics 0625 — Topic 6: Space Physics

Question 1

The Earth rotates on its axis once every 24 hours. In which direction does it rotate when viewed from above the North Pole?

AClockwise BAnticlockwise (west to east) CIt alternates direction DIt does not rotate

Question 2

Seasons on Earth are caused by:

AThe Earth being closer to the Sun in summer BThe tilt of the Earth's axis at 23.5° combined with its orbit around the Sun CThe Moon's gravitational pull on Earth DChanges in the Sun's energy output

Question 3

A full Moon occurs when:

AThe Moon is between the Earth and the Sun BThe Earth is between the Sun and the Moon CThe Moon is at right angles to the Earth-Sun line DThe Moon passes through Earth's shadow

Question 4

The International Space Station (ISS), where Tim Peake conducted experiments, orbits at a radius of 6800 km from Earth's centre with a period of 5500 s. Calculate its orbital speed using v = 2πr/T.

A3.9 km/s B7.8 km/s C11.2 km/s D15.5 km/s

Question 5

At the June solstice, the North Pole is tilted towards the Sun. What does this mean for the UK?

AShorter days and longer nights BLonger days and shorter nights CEqual length days and nights DNo sunlight at all

Question 6

During a first quarter Moon, approximately what fraction of the Moon's visible face is illuminated?

ANone BOne quarter COne half DThree quarters

Question 7

A comet orbits the Sun with an orbital radius of 6.0 × 10¹² m and a period of 9.5 × 10⁸ s. What is its average orbital speed?

A2.0 × 10⁴ m/s B4.0 × 10⁴ m/s C6.3 × 10³ m/s D4.0 × 10³ m/s

Question 8

Which planet is the largest in the Solar System?

ASaturn BNeptune CJupiter DUranus

Question 9

The outer planets (Jupiter, Saturn, Uranus, Neptune) are called gas giants or ice giants. Which characteristic do they share?

AThey all have solid rocky surfaces BThey are all smaller than Earth CThey have thick atmospheres and no well-defined solid surface DThey all have exactly the same number of moons

Question 10

Mars is approximately 2.3 × 10¹¹ m from the Sun. How long does it take light from the Sun to reach Mars?

A77 s B770 s C7700 s D230 s

Question 11

In the accretion model of Solar System formation, what role does gravity play?

AIt pushes particles apart to form planets BIt pulls particles together, building up larger and larger bodies CIt only affects the Sun, not the planets DIt creates electromagnetic radiation

Question 12

ESA's Rosetta mission studied Comet 67P. Why do comets speed up as they approach the Sun?

AThe Sun's radiation pushes them faster BThey lose mass and accelerate CGravitational potential energy converts to kinetic energy as they fall towards the Sun DSolar wind accelerates them

Question 13

A student at a Scottish Dark Sky Observatory measures the gravitational field strength on Earth's surface as 9.8 N/kg. On the Moon, g = 1.6 N/kg. A telescope weighing 49 N on Earth would weigh approximately what on the Moon?

A1.6 N B8.0 N C49 N D80 N

Question 14

Which statement about planetary orbits is correct?

AA planet moves at constant speed throughout its elliptical orbit BA planet moves faster when it is further from the Sun CA planet moves faster when it is closer to the Sun DA planet's speed is determined only by its mass

Question 15

Neptune is the most distant planet from the Sun. What can be said about its orbital period compared to Mercury's?

ANeptune has a much shorter orbital period BNeptune has the same orbital period CNeptune has a much longer orbital period DOrbital period does not depend on distance from the Sun

Question 16

The gravitational field strength at the surface of a planet depends on:

AThe planet's colour and temperature only BThe planet's mass and radius CThe planet's distance from the Sun only DThe number of moons the planet has

Question 17

The Sun produces energy by:

ABurning hydrogen gas like a fire BFusing hydrogen nuclei into helium nuclei CSplitting uranium atoms apart DConverting helium into hydrogen

Question 18

Which statement about the Sun is correct?

AThe Sun is the largest star in the Milky Way BThe Sun is a small dwarf star CThe Sun is a medium-sized star in the main sequence stage DThe Sun is a red giant star

Question 19

The Sun emits ultraviolet radiation. What is one effect of this on Earth?

AIt causes the tides BIt can cause sunburn and skin damage CIt creates the seasons DIt causes earthquakes

Question 20

Nuclear fusion in the Sun requires extremely high temperatures because:

AHydrogen is a gas at room temperature BThe enormous temperature gives hydrogen nuclei enough kinetic energy to overcome electrostatic repulsion CCold hydrogen cannot burn DHelium needs to be heated to become hydrogen

Question 21

Compared to the visible light it emits, the infrared radiation from the Sun has:

AA shorter wavelength and higher frequency BA longer wavelength and lower frequency CThe same wavelength and frequency DA shorter wavelength and lower frequency

Question 22

Stars are born in:

AWhite dwarfs BBlack holes CNebulae (clouds of gas and dust) DOther stars

Question 23

During the main sequence stage, a star is stable because:

AIt has stopped producing energy BThe outward pressure from fusion balances the inward pull of gravity CIt is too cold for fusion to occur DIt is surrounded by other stars that support it

Question 24

The Milky Way is best described as a:

AGlobular cluster of a few thousand stars BSpiral galaxy containing billions of stars CSmall irregular galaxy DSingle star system with many planets

Question 25

A star is 1.9 × 10¹⁷ m from Earth. Express this distance in light-years. (1 ly = 9.5 × 10¹⁵ m)

A2.0 ly B20 ly C200 ly D0.20 ly

Question 26

After the red giant phase, a star with a mass similar to the Sun will:

AExplode as a supernova BBecome a black hole CShed its outer layers and become a white dwarf DReturn to the main sequence

Question 27

A supernova is:

AThe gradual cooling of a white dwarf BThe explosive death of a massive star CThe formation of a new star DA type of galaxy

Question 28

Which statement about neutron stars is correct?

AThey are larger than the Sun BThey are the remnants of low-mass stars CThey are incredibly dense remnants left after a supernova of a massive star DThey produce energy by nuclear fusion

Question 29

Light from a distant star observed at the Cambridge Institute of Astronomy takes 50 years to reach Earth. How far away is the star in metres? (1 ly = 9.5 × 10¹⁵ m)

A4.75 × 10¹⁵ m B4.75 × 10¹⁷ m C4.75 × 10¹⁸ m D9.5 × 10¹⁵ m

Question 30

A black hole is formed when:

AAny star runs out of fuel BA very massive star's core collapses after a supernova and gravity is so strong nothing can escape CA white dwarf cools down completely DTwo galaxies collide

Question 31

The diameter of the Milky Way is approximately:

A100 000 km B100 000 AU C100 000 light-years D100 000 parsecs

Question 32

Redshift in the light from a distant galaxy indicates that:

AThe galaxy is getting hotter BThe galaxy is moving towards us CThe galaxy is moving away from us DThe galaxy is getting smaller

Question 33

Hubble's law states that:

AAll galaxies are the same distance away BMore distant galaxies are moving away faster CCloser galaxies are moving away faster DAll galaxies move at the same speed

Question 34

CMBR was first detected in 1965 by Penzias and Wilson. What temperature does this radiation correspond to?

AAbout 2.7 K BAbout 27 K CAbout 270 K DAbout 2700 K

Question 35

If the Hubble constant H₀ = 2.2 × 10⁻¹⁸ s⁻¹, the estimated age of the Universe in seconds is:

A2.2 × 10¹⁸ s B4.5 × 10¹⁷ s C2.2 × 10⁻¹⁸ s D4.5 × 10⁻¹⁷ s

Question 36

A galaxy has a recession velocity of 3.3 × 10⁶ m/s. Using H₀ = 2.2 × 10⁻¹⁸ s⁻¹, how far away is it?

A1.5 × 10²⁴ m B7.3 × 10⁻¹² m C1.5 × 10²³ m D7.3 × 10²³ m

Question 37

The Big Bang theory is supported by the observation that:

AStars are all the same age BGalaxies in all directions show redshift, and CMBR exists uniformly in all directions CThe Universe has always been the same temperature DAll galaxies are the same distance from Earth

Question 38

Galaxy X has a recession velocity of 4.4 × 10⁵ m/s and Galaxy Y has a recession velocity of 8.8 × 10⁵ m/s. According to Hubble's law:

AGalaxy Y is twice as far away as Galaxy X BGalaxy Y is half as far away as Galaxy X CBoth galaxies are the same distance away DGalaxy Y is four times as far away as Galaxy X

Question 39

If the Universe is expanding, what was it like in the distant past?

AIt was larger and cooler BIt was smaller, denser, and hotter CIt was the same as today DIt was empty with no matter

Question 40

A galaxy at a distance of 4.5 × 10²⁴ m shows a recession velocity of 9.9 × 10⁶ m/s. Calculate H₀.

A1.1 × 10⁻¹⁸ s⁻¹ B2.2 × 10⁻¹⁸ s⁻¹ C3.3 × 10⁻¹⁸ s⁻¹ D4.4 × 10⁻¹⁸ s⁻¹

Paper 2 — Multiple Choice

Section A — 6.1.1 The Earth

Section B — 6.1.2 The Solar System

Section C — 6.2.1 The Sun as a Star

Section D — 6.2.2 Stars

Section E — 6.2.3 The Universe