Stars & Planets (WJEC GCSE Science (Double Award): Physics): Exam Questions

Jupiter has 79 moons in orbit around it. The table shows data for 4 of its moons.

Use information from the table above to answer the following questions.

(i) State which moon has the highest mean temperature.

[1]

(ii) For the solar system, as the orbit radius increases around the Sun, the mean temperature of the planets generally decreases.

Explain why the orbit radius of the moons around Jupiter does not affect their temperatures in the same way.

[2]

(iii) Peter states that as Callisto has the longest orbit time it must be the largest moon.

Determine whether Peter's claim is correct.

[1]

(iv) Peter correctly notices that Ganymede has an orbit time that is exactly double Europa's.

Peter suggests that as the orbit time doubles, the orbit radius also doubles.

Use only the data for Ganymede and Europa to determine whether Peter's claim is true.

[1]

(i) Two of the statements listed below are correct. One correct statement has already been ticked.

Tick (✓) one more box to show the other correct statement.

[1]

• An Astronomical Unit (AU) is the mean distance that separates the Earth and the Sun.

• A light year is a measurement of time.

• A light minute is the distance travelled by light in 60 seconds.

• A light year is smaller than a light second.

(ii) Both Earth and Jupiter travel in elliptical paths around the Sun.

As they orbit the Sun the closest distance between Jupiter and Earth is 588 000 000 km. This is equivalent to 3.92 AU.

Calculate the distance, in km, that separates the Earth and the Sun.

[2]

(1 AU = Earth to Sun distance)

Distance = .......... km

Explain, in terms of forces and nuclear fusion, the life cycle of a high-mass star, from its position on the main sequence to its 'death'.

The number of planets in our Solar System totals eight.

Briefly outline the difference between the structure of the inner and outer four planets and explain how they originated.

One of the most useful diagrams in astrophysics is the Hertzsprung-Russell (HR) diagram. It was developed separately by two astronomers, the Danish astronomer Ejnar Hertzsprung and the American astronomer Henry Norris Russell. Their combined diagram shows that the relationship between the temperature and luminosity of a star is not random and stars fall into distinct groups. These are seen in the Hertzsprung-Russell diagram below which shows the properties of stars.

Spica is a very large blue star on the main sequence, approximately 10 times the mass of the Sun. Spica is 261 light-years from Earth.

(i) Explain, in terms of forces, why Spica is currently stable.

[2]

(ii) Spica is 261 light-years from Earth. State what this means.

[1]

The Sun is also on the main sequence. It is a yellow dwarf star.

Explain, in terms of forces, the reactions within the Sun and the properties shown on the HR diagram, how the Sun will change during the remainder of its life cycle.

Our solar system formed about 4.5 billion years ago.

Tick (✓) the boxes next to the two correct statements.

Our solar system originated from a cloud of gas and dust.

The heavy elements in our solar system originated from a supernova.

The Sun formed when large asteroids clumped together.

At the end of our Sun's life, heavy elements will be returned to space.

The table gives information about some planets in our solar system.

Use the information in the table to answer the following questions.

(i) State which planet is closest in size to Earth.

[1]

(ii) State which planet has a day length longer than its year.

[1]

(iii) Natalie says the larger the gas giant planet the longer its days are.

Rhian says Natalie is wrong.

Explain whether you agree with Natalie or Rhian.

[2]

Arcturus is a red giant star, 37 light-years away from Earth.

(i) State how long light from Arcturus takes to reach the Earth.

[1]

time = ............................................................

(ii) Use your answer to (i) and an equation from page 2 to determine the distance of Arcturus from Earth in metres.

(1 year = 31 600 000 s, speed of light, = 3 × 10⁸ m/s)

[3]

distance = ........................................................ m

The Hertzsprung-Russell (HR) diagram below shows the properties of different stars.

(i) The Sun and Arcturus have different colours.

Use information from the diagram to compare their other properties.

[2]

(ii) The Sun is currently on the main sequence.

At the end of this stage of its life cycle it will become a red giant like Arcturus.

Explain, in terms of forces and fusion, why the Sun will become a red giant.

[4]

The following diagrams show the life cycle of two different mass stars.

Diagram 1 shows how a star that is similar in mass to our Sun changes with time.

Diagram 2 shows the changes for a star that is 8 times more massive than our Sun.

Complete the labelling on diagrams 1 and 2, using words or phrases from the box below.

Words or phrases can be used once, more than once or not at all.

Underline the word or phrase in the brackets which correctly completes each sentence.

(i) A main sequence star is stable because its gravitational force is

( less than / equal to / greater than ) the force caused by its radiation pressure.

(ii) Stars generate their energy by the ( burning / fusion / fission ) of increasingly heavier elements.

(iii) During the final stages in the life cycle of some stars heavy elements are ejected when the star becomes a ( gaseous giant planet / supernova / supergiant ).

The collapse of a cloud of gas and dust combined with these heavy elements can eventually form a ( Solar System / galaxy / Universe ).

This question is about the Solar System.

Complete the following sentence.

The Solar System was formed by the collapse of a cloud of .......... and

.......... .

The table shows some information about planets in our Solar System.

Use the information in the table to answer the questions that follow.

(i) Describe how the temperature on a planet depends on the distance from the Sun.

[1]

(ii) Identify the planet that does not follow this trend.

[1]

(iii) Pallas is an asteroid found in the asteroid belt.

I. Estimate its temperature. .......... °C

[1]

II. Estimate its orbital time. .......... years

[1]

(iv) It is suggested that the greater the mass of a planet, the more moons that will orbit around it. Explain whether the data agrees with this suggestion.

[2]