Space Physics Exam Questions for IGCSE Physics

This guide covers the question types in the space physics section of IGCSE Physics, the smallest topic but still worth learning.

Question type 1: Solar system knowledge

Name the planets in order. Distinguish between planets, moons, asteroids and comets. Describe the shape of planetary orbits (elliptical, nearly circular for most planets).

Question type 2: Gravitational field strength

Use W = mg with different values of g for different locations (Earth: 10 N/kg, Moon: 1.6 N/kg).

Worked example: An astronaut has a mass of 80 kg. Calculate their weight on the Moon.

W = mg = 80 x 1.6 = 128 N.

Question type 3: Life cycle of stars

Describe the stages for a star like the Sun: nebula, protostar, main sequence, red giant, planetary nebula, white dwarf.

Describe the stages for a massive star: nebula, protostar, main sequence, red supergiant, supernova, neutron star or black hole.

Know that gravity pulls the star inward, and the radiation pressure from fusion pushes outward. On the main sequence, these forces balance.

Question type 4: Evidence for the Big Bang

Explain red-shift: light from distant galaxies is shifted towards the red end of the spectrum, showing they are moving away. More distant galaxies have a greater red-shift, meaning they move faster. This supports the idea that the universe is expanding.

Explain cosmic microwave background radiation: low-level microwave radiation fills the universe in all directions. It is the cooled remnant of radiation from the Big Bang.

Practice approach

This section is mostly descriptive. Practise writing structured descriptions of the stellar life cycle and the evidence for the Big Bang.