If the rate of hydrogen fusion within the sun were to decrease, the core of the sun would:?

Question

A) contract and decrease in temp
B) contract and increase in temp
C) expand and increase in temp
D) expand and decrease in temp
E) stay the same size but increase in temp

Answer 1

Hi. Fusion is what helps the Sun to prevent collapse, so three answers are ruled out. When the Sun contracts the pressure increases and fusion starts to increase, resulting in a higher temperature. So I would say B is correct.

Answer 2

The sun remains its current size due to a balance between the heat in the core trying to expand it, and gravity trying to contract it.
So if hydrogen fusion is what creates the heat in the core and that fusion decreases, then there is less heat, right?
So if gravity is trying to contract the sun and you take away the one thing stopping it, what do you think would happen? It would contract, wouldn't it?

As for the "increase" or "decrease" in temperature, that's still basic physics but a little further along in the textbook.
If the sun contracts, the gravitational energy of contraction would be converted to kinetic energy (heat), which would be directed to the core and would cause the temperature to rise.

Answer 3

The core would contract and decrease in temp. It sounds like your describing the end of the main sequence of a star. In this phase Hydrogen fusion decreases and the sun is preparing for it's last ditch effort at hydrogen fusion not from the core but from the shell. Of course this doesn't last and eventually the star moves into it's next stage of life.

Answer 4

I am thinking B) because the the heat from the nuclear reaction pushes the material out. This is balanced by the gravitational force pushing it inside. So if the heat was to decrease u will have lower temperature BUT contraction will cause an increase in temperature and gravity force would dominate pulling the material inwards to a new equilibrium position where the two forces are again balanced.