Stars
Cambridge IGCSE Physics (0625) · Unit 6: Space physics · 6 flashcards
Stars is topic 6.2.2 in the Cambridge IGCSE Physics (0625) syllabus , positioned in Unit 6 — Space physics , alongside The Earth, The Solar System and The Sun as a star.
This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical).
The deck below contains 6 flashcards — covering the precise wording mark schemes reward.
What the Cambridge 0625 syllabus says
Official 2026-2028 specThese are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.
- State State that: (a) galaxies are each made up of many billions of stars (b) the Sun is a star in the galaxy known as the Milky Way (c) other stars that make up the Milky Way are much further away from the Earth than the Sun is from the Earth (d) astronomical distances can be measured in light-years, where one light-year is the distance travelled in (the vacuum of) space by light in one year
- Know Know that one light-year is equal to 9.5 x 1015 m Supplement
- Describe Describe the life cycle of a star: (a) a star is formed from interstellar clouds of gas and dust that contain hydrogen (b) a protostar is an interstellar cloud collapsing and increasing in temperature as a result of its internal gravitational attraction (c) a protostar becomes a stable star when the inward force of gravitational attraction is balanced by an outward force due to the high temperature in the centre of the star (d) all stars eventually run out of hydrogen as fuel for the nuclear reaction (e) most stars expand to form red giants and more massive stars expand to form red supergiants when most of the hydrogen in the centre of the star has been converted to helium (f) a red giant from a less massive star forms a planetary nebula with a white dwarf star at its centre (g) a red supergiant explodes as a supernova, forming a nebula containing hydrogen and new heavier elements, leaving behind a neutron star or a black hole at its centre (h) the nebula from a supernova may form new stars with orbiting planets Supplement
Light travels at approximately 3.0 x 10^8 m/s in space. Calculate the distance, in metres, of one light-year.
Distance = speed x time.
Time = 1 year = 365.25 days x 24 hours x 60 minutes x 60 seconds = 31,557,600 s
Distance = (3.0 x 10^8 m/s) x (31,557,600 s) = 9.47 x 10^15 m. One light-year is the distance light travels in a year, so we multiply the speed of light by the number of seconds in a year.
State three facts about the Sun's location and relation to other stars and galaxies.
1. The Sun is a star.
2. The Sun is located in the Milky Way galaxy.
3. Other stars in the Milky Way are much further away from Earth than the Sun is.
Calculate the distance, in meters, that light travels in 4.6 years. State your answer in standard form. You may use the following value: 1 light-year = 9.5 x 10¹⁵ m
Distance = (Number of light-years) x (Distance of 1 light-year)
Distance = 4.6 x 9.5 x 10¹⁵ m
Distance = 4.37 x 10¹⁶ m
This calculation uses the definition of a light-year to find the distance light travels in 4.6 years.
Describe what is meant by the term 'one light-year'.
One light-year is the distance that light travels through a vacuum in one year. It is equal to 9.5 x 10¹⁵ meters.
Describe the key stages in the life cycle of a star, starting from an interstellar cloud of gas and dust and ending with either a white dwarf or a black hole.
1. Interstellar Cloud: Stars form from interstellar clouds of gas and dust, mainly hydrogen.
2. Protostar: The cloud collapses under gravity, increasing temperature.
3. Stable Star: Nuclear fusion begins; outward pressure from fusion balances inward gravity.
4. Red Giant/Supergiant: Hydrogen fuel depletes; core contracts, outer layers expand and cool.
5a. White Dwarf: For smaller stars, the red giant sheds its outer layers as a planetary nebula, leaving behind a white dwarf.
5b. Supernova/Neutron Star/Black Hole: For massive stars, the red supergiant explodes as a supernova. The core collapses to form a neutron star, or a black hole if the star is massive enough.
Explain why a protostar increases in temperature as it collapses under its own gravitational attraction.
As the interstellar cloud collapses, its gravitational potential energy is converted into kinetic energy. The increased kinetic energy results in increased particle motion, causing the temperature of the gas and dust to rise.
More topics in Unit 6 — Space physics
Stars sits alongside these Physics decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Related Physics guides
Long-read articles that go beyond the deck — cover the whole subject's common mistakes, high-yield content and revision pacing.
How to study this Stars deck
Start in Study Mode, attempt each card before flipping, then rate Hard, Okay or Easy. Cards you rate Hard come back within a day; cards you rate Easy push out to weeks. Your progress is saved in your browser, so come back daily for 5–10 minute reviews until every card reads Mastered.
Study Mode
Space to flip • ←→ to navigate • Esc to close
You're on a roll!
You've viewed 10 topics today
Create a free account to unlock unlimited access to all revision notes, flashcards, and study materials.
You're all set!
Enjoy unlimited access to all study materials.
Something went wrong. Please try again.
What you'll get:
- Unlimited revision notes & flashcards
- Track your study progress
- No spam, just study updates