Physics 8.1.2

Question 1

Explain how the Sun was Formed: (4)

Answer 1

-Massive Cloud of Dust & Gas in Space (Nebula).

-Gravity (In the Centre) Pulled this Cloud Together, into a Giant Ball.

-The Nebula Collapsed in on its Centre, due to the Immense Gravity. The Centre of this Ball got v. Dense & Hot, & so Began to Rotate.

-Eventually, Nuclear Fusion was able to Begin, due to the Immense Thermal Energy Present. A Dense ‘Protostar’ was Formed- our Sun.

Question 2

What are the 2 Forces Exerted by a Star’s Core to keep the Star in Equilibrium? (2)

Answer 2

-Outward Pressure.

-Inward Gravity.

Question 3

The Inward Force of Gravity in Stars (Caused by the Star’s Core)…

Answer 3

Is an Attractive Force, which Pulls the Outer Layers Inwards.

Question 4

The Outwards Force of Pressure in Stars (Caused by the Star’s Core)…

Answer 4

Is an Outwards Force, which is Exerted from the Expanding Hot Gases, Inside the Star’s Core.

Question 5

Why does a Star need to Maintain Equilibrium? (2)

Answer 5

-If Inward Gravity > Outward Pressure, the Star would Contract, or ‘Crunch’, in on itself’s Core.

-If Outward Pressure > Inward Gravity, the Star would Explode.

Question 6

What Happens to the Equilibrium of a Star if the Temperature Increases?

Answer 6

Higher Rate of Nuclear Fusion in the Core. More Kinetic Energy Released. Increase in Outward Pressure Force Caused. So now Outward Pressure > Inward Gravity. So Star will Expand (maybe Explode).

Question 7

What Happens to the Equilibrium of a Star if the Temperature Decreases?

Answer 7

Slower Rate of Nuclear Fusion in the Core. Less Kinetic Energy Released. Decrease in Outward Pressure Force Caused. So now Inward Gravity > Outward Pressure. So Star will Contract, or ‘Crunch’ in on itself’s Core.

Question 8

In the Core of a Star, in Order to Maintain Constant Temp., & so Maintain Constant Equilibrium, there is a Constant Rate of…

Answer 8

Nuclear Fusion. (Releases KE & Therm.En..)