Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Astrophysics
156 practice questions
Topics covered
Practice questions
71–78 of 78 · Easy
Question 71
4 marks · Easy
Answer and see the solution →Scientists use both red-shift and the cosmic microwave background (CMB) radiation to support their model of the universe.
(a)[2 marks]State what is meant by cosmic microwave background (CMB) radiation.
(b)[2 marks]Explain how observations of both red-shift and the CMB together provide evidence for the Big Bang.
Question 72
4 marks · Easy
Answer and see the solution →Light from the Sun has a wavelength of 500 nm. Light observed from a distant galaxy shows the same absorption line at a wavelength of 560 nm.
(a)[1 mark]Calculate the change in wavelength for the absorption line.
(b)[3 marks]The speed of light is m/s. Using the Doppler effect equation , calculate the speed at which the galaxy is moving away from Earth. Give your answer in km/s.
Question 73
4 marks · Easy
Answer and see the solution →The diagram below shows part of our solar system, with the Sun, the Earth, and an artificial satellite orbiting Earth.
Part of the Solar System: Sun, Earth, Satellite (a)[1 mark]What keeps the satellite in orbit around the Earth? State the force.
(b)[1 mark]Name the unit used to measure the gravitational field strength on the surface of a planet.
(c)[2 marks]Is the strength of gravity greater on Earth or on the Moon? Explain briefly.
Question 74
4 marks · Easy
Answer and see the solution →The table below gives information about three planets in our solar system.
Planet Surface Temperature (°C) Class Mercury 167 M Sirius 9940 A Sun 5500 G (a)[2 marks]What is the class and typical colour of the Sun's light according to its surface temperature?
(b)[2 marks]Which star in the table is hottest? What would its colour be?
Question 75
4 marks · Easy
Answer and see the solution →A satellite travels in a circular orbit around Earth. The radius of its orbit is 7,000 km and it takes 2 hours to complete one orbit.
(a)[1 mark]Calculate the circumference of the orbit. Give your answer in km.
(b)[2 marks]Calculate the orbital speed of the satellite in km/h. Use: speed = distance/time.
(c)[1 mark]What is the correct SI unit for speed? (Give the symbol.)
Question 76
4 marks · Easy
Answer and see the solution →The table below shows some information about two planets in our solar system and a moon of one of the planets.
Name Average distance from Sun (×10^8 km) Type Orbital time period (Earth years/days) Venus 1.08 Planet 0.6 years Earth 1.50 Planet 1.0 year Moon - Moon of Earth 27.3 days (a)[1 mark]State the unit used for the average distance of planets from the Sun in the table.
(b)[1 mark]Explain why the Moon is called a 'natural satellite' and not a planet.
(c)[2 marks]Which of the two planets in the table has a stronger gravitational attraction from the Sun? Explain your answer using information from the table.
Question 77
4 marks · Easy
Answer and see the solution →Stars can be classified by their colour and temperature. The diagram below shows stars of different classes.
Class Surface temperature (K) Colour O >33,000 Blue G 6,000–5,200 Yellow M 2,000–3,700 Red (a)[2 marks]Which class does the Sun belong to? State the reason for your answer.
(b)[2 marks]Describe how the colour of a star tells us about its surface temperature.
Question 78
4 marks · Easy
Answer and see the solution →A weather satellite completes an orbit around Earth every 6 hours at an average orbital radius of 12,000 km.
(a)[1 mark]State the SI unit for the orbital radius in this context.
(b)[1 mark]Write the formula for calculating the speed of an orbiting satellite using its orbital radius and time period.
(c)[2 marks]Calculate the orbital speed of the satellite. Give your answer to 2 significant figures.