AQA GCSE PHYSICS · PAPER 2 · FOUNDATION & HIGHER
Exam Practice: Life cycle of a star
Life cycle of a star · Space physics · Lesson 2 of 4 · 16 marks · 17 minutes
|
Name |
|
Date |
|
Instructions
• Answer all the questions.
• Write your answers in the spaces provided.
• The marks for each question are shown in brackets - use this as a guide to how much to write.
• The answers are on separate pages at the back. Attempt every question before you look at them.
• Answer all questions. Use the mark allocation as a guide to how much to write.
Question 1 STATE (2 marks)
Name the stages in the life cycle of a star like our Sun after the main sequence.
|
|
|
|
|
|
(Total for Question 1 = 2 marks)
Question 2 EXPLAIN (3 marks)
Explain why a star on the main sequence is stable.
|
|
|
|
|
|
|
|
(Total for Question 2 = 3 marks)
Question 3 DESCRIBE (4 marks)
Describe the life cycle of a star that is much more massive than the Sun.
|
|
|
|
|
|
|
|
|
|
|
|
(Total for Question 3 = 4 marks)
Question 4 EXPLAIN (3 marks)
Explain why some elements heavier than iron are found on Earth even though they cannot be made in the main sequence.
|
|
|
|
|
|
|
|
(Total for Question 4 = 3 marks)
Question 5 EXPLAIN (4 marks)
Explain how the Sun formed and why the Sun is stable.
|
|
|
|
|
|
|
|
|
|
|
|
(Total for Question 5 = 4 marks)
TOTAL FOR PAPER = 16 MARKS
|
|
Answers and mark scheme
Check your answer only once you have written one.
Question 1 (2 marks)
Red giant, then white dwarf (then black dwarf).
• Red giant 1 mark
• White dwarf 1 mark
Question 2 (3 marks)
The inward force of gravity is balanced by the outward pressure from the energy released by nuclear fusion, so the star neither collapses nor expands.
• Gravity acts inwards 1 mark
• Fusion energy gives outward pressure 1 mark
• The forces balance 1 mark
Question 3 (4 marks)
A cloud of dust and gas collapses under gravity to form a protostar, then a main sequence star. When hydrogen runs out it expands into a red supergiant, then explodes as a supernova, leaving a neutron star or a black hole.
• Nebula / protostar / main sequence 1 mark
• Red supergiant 1 mark
• Supernova 1 mark
• Neutron star or black hole 1 mark
Question 4 (3 marks)
Elements heavier than iron are made in the explosion of a supernova, which has enough energy. The explosion throws the elements into space, where they form part of new stars and planets.
• Supernova forms heavier elements 1 mark
• Elements thrown into space 1 mark
• Incorporated into new stars and planets 1 mark
Question 5 (4 marks)
Dust and gas were pulled together by gravity. The star got hot and dense enough for nuclear fusion to start. It is stable as the inward gravitational force balances the outward pressure from fusion energy.
• Gravity pulls dust and gas together 1 mark
• Fusion begins 1 mark
• Gravity acts inwards 1 mark
• Balanced by outward pressure 1 mark