Topic 7 🔭⭐️

Question 1

Why does your weight vary across planets?

Answer 1

• Your weight is dependent on gravity.
• The gravitational field strength of a planet varies depending on size of the planet.

Question 2

What is the gravitational field strength on Earth?

Answer 2

Approximately 10 N/kg

Question 3

What does our solar system consist of?

Answer 3

• The sun (our star)
• 8 planets
• The planets natural satellites
• Dwarf planets
• Comets and asteroids

Question 4

Name the planets in order.

Answer 4

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 5

Describe the orbits of the moons, planets, comets and artificial satellites.

Answer 5

They orbit in an elliptical shape.

Question 6

Describe the Steady State Theory.

Answer 6

The Steady State theory says that the universe has always existed but is expanding and creating matter to counteract the loss in density.

Question 7

Describe the Big Bang theory.

Answer 7

The Big Bang theory states that the universe expanded from a very smaller dense point about 14 billion years ago ago.

Question 8

What is red-shift?

Answer 8

A perceived increase in the wavelength of light due to the source moving away from the observer.

Question 9

What does red-shift provide evidence for?

Answer 9

• The universe is expanding
• This supports the Big Bang theory

Question 10

What does the Big Bang theory suggest?

Answer 10

The entire universe started from a very small, hot and dense region in space.

Question 11

Compare the observed red-shift of two galaxies, one further away than the other.

Answer 11

• The galaxy that is further away is travelling faster.
• The observed red-shift is greater the further away it is

Question 12

What did scientists observe to provide evidence that the universe is expanding at an ever faster rate?

Answer 12

They observed supernovae, which suggested that galaxies are moving away at an ever faster rate.

Question 13

What does CMBR stand for?

Answer 13

Cosmic Microwave Background Radiation

Question 14

What does CMBR provide further evidence for?

Answer 14

• The Big Bang Theory
• It it believed that CMBR originates from radiation produced in the Big Bang

Question 15

How does the existence of CMBR support the expansion of the universe?

Answer 15

• It is thought that gamma radiation was released in the Big Bang
• The expansion of the universe has stretched this radiation, resulting in the microwave radiation present today.

Question 16

What fact determines the type of lifecycle a star undergoes?

Answer 16

The size of the star

Question 17

Which two phases do all the stars of the same or greater size than the sun undergo?

Answer 17

1. Protostar phase
2. Main sequence phase

Question 18

What do stars like the sun become at the end of their life-cycle?

Answer 18

A black dwarf

Question 19

What two things can stars much bigger than the universe become at the end of their lifecycle?

Answer 19

1. Neutron star
2. Black hole

Question 20

What two phases do stars of similar size to the sun go through between being a main sequence star and a black dwarf?

Answer 20

1. Red giant
2. White dwarf

Question 21

What two phases do stars of greater size than the sun go through between being a main sequence star and a neutron star/black hole?

Answer 21

1. Red supergiant
2. Supernova

Question 22

Describe the transition of the star from the nebula stage to the main sequence.

Answer 22

• Nebula increases in size until it is pulled in due to its gravity, causing GPE to turn into KE.
• The collisions between particles cause this kinetic energy to turn into thermal energy.
• Eventually the nebula will become dense and hot enough to begin fusion.

Question 23

What occurs in the stage when a star is a main sequence star?

Answer 23

• The fusion in the star releases energy
• This energy balances out with the gravitational potential energy leaving the star
• The star is in equilibrium so will not collapse due to gravity or expand due to radioactive behaviour. It is table

Question 24

What environment is required for nuclear fusion to occur?

Answer 24

Higher temperature and high pressure