Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Cosmology
37 practice questions
Topics covered
Practice questions
31–37 of 37
Question 31
2 marks · Normal
Answer and see the solution →What is meant by the term ‘red-shift’ and what does it suggest about the universe?
Question 32
4 marks · Easy
Answer and see the solution →A student is looking at the light spectra from two galaxies, Galaxy A and Galaxy B, using a spectrometer. She notices that the absorption lines for Galaxy B are further towards the red end of the spectrum than those in Galaxy A.
(a)[2 marks]What is the name for the shift of absorption lines towards the red end of the spectrum, and what does it indicate about a galaxy’s motion relative to us?
(b)[2 marks]If Galaxy B’s absorption lines have shifted more than Galaxy A’s, what can you deduce about the relative speeds and distances of the two galaxies from us?
Question 33
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 34
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 35
5 marks · Normal
Answer and see the solution →A student is studying two galaxies, Galaxy X and Galaxy Y. She notices that the absorption lines in the spectrum of Galaxy Y are shifted more towards the red end of the spectrum than those of Galaxy X.
(a)[2 marks]Describe what is meant by the term 'red-shift' in the context of light spectra from galaxies.
(b)[2 marks]Explain what the observation about the absorption lines tells us about the relative velocities and distances of Galaxy X and Galaxy Y from Earth.
(c)[1 mark]State how this evidence is related to the theory that the universe began with a Big Bang.
Question 36
5 marks · Normal
Answer and see the solution →Light from a galaxy has a measured wavelength of 660 nm. The same absorption line in the Sun's spectrum has a wavelength of 600 nm.
(a)[1 mark]Calculate the change in wavelength observed for the galaxy's light compared to the Sun's light.
(b)[3 marks]Using the Doppler equation, calculate the speed at which the galaxy is moving away from Earth. Use the speed of light as m/s.
(c)[1 mark]State whether this galaxy is moving towards or away from Earth, and explain your answer.
Question 37
4 marks · Normal
Answer and see the solution →Astronomers use two main types of evidence to support the idea that the universe began with a Big Bang: cosmic microwave background (CMB) radiation and red-shift of galaxies.
(a)[2 marks]Describe what cosmic microwave background (CMB) radiation is.
(b)[2 marks]Explain how CMB radiation and red-shift together act as evidence for the Big Bang theory.