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Flashcards in Nuclear physics Deck (14)
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1
Q

Name the two substances in common use in nuclear reactors, and why can we use them?

A

Uranium-235 and Plutonium-239

They are fissile or fissionable

2
Q

Define nuclear fission

A

The splitting of an atomic NUCLEUS

3
Q

First step of nuclear fission

A

Uranium-235 or Plutonium-239 nucleus absorbs a neutron

4
Q

Second step of nuclear fission

A

The nucleus splits into two smaller nuclei and two or three neutrons and energy is released

5
Q

Third step of nuclear fission

A

The neutrons are fired off with enough energy that they might cause the fission of other nuclei if they collide

6
Q

How does nuclear fission work in a power station?

A

Fission releases energy, which heats water and turns it into steam to spin a turbine, which is connected to a generator that generates electricity

7
Q

Advantages of fusion over fission

Advantages of both over conventional electricity generation

A

Plentiful supply of fuel (formed from sea water and lithium) as opposed to limited amounts of uranium and plutonium
No radioactive byproducts
Fail-safe and shuts down automatically if there is a fault
Both give out no greenhouse gases

8
Q

How do stars release energy?

A

Nuclear fusion

9
Q

When do stars form? When do planets form?

A

When enough dust and gas from space is pulled together by gravitational attraction
When smaller masses form and are attracted by a larger mass i.e. a star

10
Q

At the beginning of the universe, what did it contain?

Why does it now contain a large variety of elements?

A

Only hydrogen
Fusion in stars - 2H fused to form He, 2He fused to form Be, etc. Supernovas (explosions of very big stars) then distribute them across the universe

11
Q

What is the main sequence period of a star?

A

A period in its life cycle wherein the forces are balanced (gravity balances against the outwards forces from explosive fusion), making it stable

12
Q

What determines which life cycle a star goes through?

A

The size

13
Q

Describe the life cycle of a star about the same size as the Sun

A

Protostar -> Main sequence star -> Red Giant -> White Dwarf -> Black Dwarf

14
Q

Describe the life cycle of a star much bigger than the Sun

A

Protostar -> Main sequence star -> Red Super Giant -> Supernova -> Neutron Star OR Black hole