Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Astrophysics
156 practice questions
Topics covered
Practice questions
121–130 of 156
Question 121
4 marks · Normal
Answer and see the solution →The diagram shows lines on the spectrum of light from two galaxies, Q and R, at different observed wavelengths.
(a)[2 marks]State which galaxy, Q or R, is moving away from Earth faster. Justify your answer using the spectrum diagram.
(b)[2 marks]The normal wavelength of a particular line in a laboratory is 590 nm. For Galaxy Q, this line is observed at 594 nm. For Galaxy R, it is observed at 600 nm. Calculate the change in wavelength () for both galaxies.
Question 122
3 marks · Normal
Answer and see the solution →A sodium lamp on Earth emits a spectral line with a wavelength of 589 nm. The same line from a distant galaxy is observed at 600 nm.
Calculate the red-shift () of light from this galaxy. Use:\n\[ z = \frac{\Delta \lambda}{\lambda_0} \] where is the original wavelength.
Question 123
3 marks · Normal
Answer and see the solution →Describe two scientific arguments that support the Big Bang theory, other than red-shift.
Question 124
3 marks · Normal
Answer and see the solution →A table below shows observed red-shift (z) values for different galaxies at increasing distances from Earth.
Red-shift and distance for several galaxies Galaxy Distance (million light-years) Red-shift (z) A 100 0.005 B 200 0.010 C 400 0.020 D 600 0.030 (a)[2 marks]Describe the relationship between galaxy distance and red-shift shown in the table.
(b)[1 mark]Suggest what this relationship supports about the universe.
Question 125
1 mark · Easy
Answer and see the solution →State the name given to the radiation that is considered the afterglow of the Big Bang and is detected in all directions of the universe.
Question 126
2 marks · Easy
Answer and see the solution →Light from a distant galaxy has a wavelength of 550 nm, while the same spectral line measured from our Sun is at 500 nm. Calculate the speed at which the galaxy is moving away from Earth. (speed of light m/s)
Question 127
2 marks · Easy
Answer and see the solution →Explain how the cosmic microwave background (CMB) radiation supports the Big Bang theory. Give two points in your answer.
Question 128
1 mark · Easy
Answer and check →Which observation about distant galaxies provides evidence that the universe is expanding?
- A.Their light is red-shifted.
- B.Their light is blue-shifted.
- C.Their light is unchanged.
- D.They emit only microwaves.
Question 129
1 mark · Easy
Answer and see the solution →A scientist observes that the absorption lines in the spectrum of a distant galaxy have moved towards longer wavelengths than those from our Sun. State the name of this effect.
Question 130
3 marks · Easy
Answer and see the solution →The universe is thought to have begun with a huge explosion called the Big Bang.
(a)[1 mark]State one observation from distant galaxies that supports the idea that the universe is expanding.
(b)[2 marks]Describe what the cosmic microwave background (CMB) radiation is.