Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GCSE Physics > Unit 2: 7 - Energy From The Nucleus > Flashcards

Unit 2: 7 - Energy From The Nucleus Flashcards

0
Q

What are the 2 isotopes most commonly used in fission reactions?

A

Uranium-235 and Plutonium-239

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What is nuclear fission?

A

The separation of an atomic nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the most common naturally occurring uranium element? What is the problem with it?

A

Uranium-238. It is non-fissionable.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the special name used for the substance used in uranium reactors?

A

‘Enriched’ uranium, which contains about 2-3% uranium-235.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

For fission reactions to take place, a _______ must be _______ at the unstable nuclei.

A

A neutron must be fired at the unstable nuclei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the nucleus split into?

A

2 daughter nuclei, and some neutrons get ejected. (3 in the case of uranium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The energy released in nuclear fission is much _____ than that of chemical reactions.

A

Greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The splitting of a nucleus begins a ______

A

Chain reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is nuclear fusion?

A

The process of forcing 2 nuclei close enough together to create a new nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In what natural process does nuclear fusion take place?

A

The energy release in stars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the conditions required for nuclear fusion?

A

Very high temperatures, around 8 million degrees Celcius.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a problem with nuclear fusion and how is it overcome?

A

Both nuclei have a strong positive charge to repel each other. Nuclear fusion requires the nuclei to be moving incredibly fast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of radiation does radon gas emit and why is this dangerous?

A

Alpha, and as it gets in through the lungs. This is dangerous as it is most ionising.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a major source of background radiation?

A

Radon gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give 3 ways workers in a nuclear power station could reduce the exposure to nuclear radiation.

A
  • Keep as far as possible from the sources
  • Spend as little time exposed as possible
  • Shield themselves with materials such as concrete and lead
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why must radioactive waste be stored securely?

A

Because it will still be unstable for many years emitting harmful radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When was the universe created and by what process?

A

The Big Bang, 13 billion years ago.

17
Q

After the first few minutes after the Big Bang, the _____ of the _____ elements formed.

A

The nuclei of the lightest elements formed.

18
Q

When the universe first came into existence, the _____ was very high. The _____ then fell over millions of years.

A

Temperature

19
Q

After the Big Bang over millions of years, ____ ____ were formed.

A

Uncharged atoms

20
Q

Before galaxies and stars were formed, the universe was a dark patchy cloud of _____ and _____.

A

Hydrogen and helium

21
Q

Dust and gas were pulled together by ____ ____ then _____ _____ to form stars.

A

Electrostatic forces then gravitational attraction.

22
Q

The resulting intense heat from the transfer of ____ energy to ____ energy during _____ _____ started ______ ______.

A

The resulting intense heat from the transfer of kinetic energy to heat during gravitational attraction started nuclear fission.

23
Q

What is a galaxy?

A

A very large group of stars.

24
Q

How many galaxies does the universe contain?

A

Billions

25
Q

What is the first part of the formation of a star?

A

Gravitational forces pull clouds of dust and gas together to form a protostar.

26
Q

What happens after the formation of a protostar?

A

The protostar becomes denser and the nuclei of hydrogen atoms and other light elements fuse together. Energy is released, the star becomes hotter and brighter and new elements are formed.

27
Q

After the protostar has run out of hydrogen, what does it become? And why?

A

It becomes a main sequence star. This is because the inward force of gravity is balanced by the outward force of radiation, making the star stable.

28
Q

What does a main sequence star with a similar size to our sun become?

A

A red giant

29
Q

What does a main sequence star with a larger mass of our sun become?

A

A red supergiant

30
Q

How does a star become a red giant?

A

A star will run out of hydrogen nuclei and swell, cool down and turn red.

31
Q

What is the next stage from a red giant, and what is the cause?

A

The star becomes a white dwarf, when helium and other light elements fuse to become heavier elements, and fusion stops. The star contracts into a white dwarf.

32
Q

What happens after the star becomes a white dwarf?

A

Eventually no more light is emitted and the star becomes a black dwarf.

33
Q

What happens after the red supergiant stage?

A

The star continues to collapse, and eventually explodes into a supernova.

34
Q

What happens in a supernova?

A

The outer layers are thrown out into space. The core is left as a neutron star.

35
Q

What is a neutron star?

A

An incredibly dense remnant of a supernova.

36
Q

What is a black hole and how is it formed?

A

If a neutron star is big enough it will form a black hole. The gravitational pull is so strong not even light can escape it.

37
Q

Give a location of a black hole.

A

In the middle of our own galaxy, the Milky Way.

38
Q

How are the chemical elements that are present on earth formed?

A

When the fusion process in stars takes place, and lighter ele nts fuse to make larger elements.

39
Q

How are elements heavier than iron formed?

A

As iron cannot be formed by fusion while releasing energy, energy has to be inputted. This happens at the final stages of the life cycle of a big star.

40
Q

How are elements distributed through the cosmos?

A

Through a supernova explosion.

41
Q

What is the heaviest element formed in a main sequence star?

A

Iron

GCSE Physics (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions