2b.4 - Nuclear Fission and Fusion

Question 1

What is nuclear fission?

Answer 1

The splitting up of an atomic nuclei

Question 2

How do nuclear reactions work? (4)

Answer 2

• Controlled chain reaction
• Atomic nuclei split up and release energy in the form of heat
• The steam heats energy
• Turns a turbine

Question 3

What nuclei is used in nuclear fission?

Answer 3

Uranium-235 and/or plutonium-239

Question 4

Explain the process of nuclear fission (4)

Answer 4

• Slow moving neutron is absorbed which makes it unstable, causing it to split
• Every split gives out two or three neutrons
• Splitting forms two smaller nuclei which are usually radioactive because wrong number of neutrons
• Releases lots of energy

Question 5

What are products of nuclear fission? (3)

Answer 5

• Two smaller nuclei
• Energy
• Two or three neutrons

Question 6

What are the pros of nuclear fission? (2)

Answer 6

• Produces lots of energy

- Fuel is cheap

Question 7

What are the cons to nuclear fission? (4)

Answer 7

• Highly radioactive products - difficult to get rid of
• Maintenance costs are high
• Dismantling plant takes decades
• Radiation leaks

Question 8

What is nuclear fusion?

Answer 8

The joining of small atomic nuclei

Question 9

What are the advantages to nuclear fusion? (2)

Answer 9

• Gives lots of energy

- Doesn’t leave behind radioactive waste

Question 10

What are the disadvantages to nuclear fusion? (3)

Answer 10

• Only happens at really high temperatures (10 million degrees)
• Needs an extremely strong magnetic field to store
• Uses more energy than is produced

Question 11

What is the first stage in the life cycle of a low mass star?

Answer 11

Nebula - Clouds of gas and dust gather due to gravity

Question 12

What is the first stage in the life cycle of a high mass star?

Answer 12

Nebula - Clouds of gas and dust gather due to gravity

Question 13

What is formed in the nebula?

Answer 13

Protostars

Question 14

What is the second stage for a low mass star?

Answer 14

Main stage star - fuse hydrogen into helium by nuclear fusion and burn for billions of years

Question 15

What is the second stage for a high mass star?

Answer 15

Red Supergiant - The star runs out of hydrogen to fuel it so cools down and swell out

Question 16

What is formed in a red supergiant?

Answer 16

Elements from helium to iron

Question 17

What is the third stage for a low mass star?

Answer 17

Red giant stage

Question 18

What is the third stage for a high mass star?

Answer 18

Supernova - A huge explosion where all elements heavier than iron are formed

Question 19

Where are all elements heavier than iron formed?

Answer 19

Supernova

Question 20

What is the forth stage for a low mass star?

Answer 20

White dwarf - No more light elements to use and it collapses

Question 21

What happens to a high mass star after a supernova? (3)

Answer 21

• Elements and debris are flung into space
• Core collapses into a neutron star
• With enough mass it can become a black hole

Question 22

What is the final stage for a low mass star?

Answer 22

Black dwarf

Question 23

What did our solar system begin as?

Answer 23

A cloud of dust and gas

Question 24

What was the first stage in the formation of the solar system?

Answer 24

A supernova disturbed the cloud

Question 25

What was the second stage in the formation of the solar system?

Answer 25

The explosion made waves that squeezed the cloud

Question 26

What was the third stage in the formation of the solar system?

Answer 26

The cloud began to collapse

Question 27

What was the fourth stage in the formation of the solar system?

Answer 27

Gravity pulled the gas and dust together

Question 28

What was the fifth stage in the formation of the solar system?

Answer 28

The cloud turned into a solar nebula and spun

Question 29

What was the sixth stage in the formation of the solar system?

Answer 29

Solar nebula became hot and dense in the centre and the disk of gas and dusk at the edges was cool

Question 30

What was the seventh stage in the formation of the solar system?

Answer 30

The disk grew thinner and continued spinning. The particles of dust and gas began to stick together

Question 31

What was the eighth stage in the formation of the solar system?

Answer 31

Some groups of particles grew bigger , these later became moons and planets