Nuclear Fission and Nuclear Fusion Flashcards
What happens during nuclear fission?
- Slow moving neutron absorbed into uranium or plutonium nucleus
- Neutrons are released, causing chain reaction
Why are nuclei produced by nuclear fission usually radioactive?
They have wrong number of neutrons in them.
What does nuclear fission produce?
Two smaller nuclei and a lot of energy
What are advantages of nuclear power?
Cheap and a lot of energy
What are the problems with nuclear power?
- Expensive to build and decommission
- Nuclear waste
- Catastrophe
What is nuclear fusion?
The joining of two light nuclei to create a larger nucleus
What is the problem with nuclear fusion?
Can only be achieved at very high temperatures (i.e 10 000 000C)
What causes the formation of a protostar?
Gravity.
Why does the temperature rise in a protostar?
Gravitational energy converts into heat energy.
When does nuclear fusion first occur for a star?
When the critical temperature is reached.
Why are main sequence stars stable?
The outward pressure and gravity are balanced.
Why are main sequence stars stable for so long?
The huge amounts of hydrogen consumed.
How are elements as heavy as iron made?
Nuclear fusion of helium.
What happens to red giants?
They eject their outer layer of dust and gas as a planetary nebula.
What is a white dwarf?
A dense solid hot core, which cools down to become a black dwarf.
