P2 - Global warming, Nuclear Radiations, Exploring our solar system

Question 1

What are radioactive materials?

Answer 1

Substances that give out nuclear radiation all the time

Question 2

What does radioactivity involve?

Answer 2

A change in the structure of the radioactive atom, and the release of one or more of the three types of nuclear radiation

Question 3

What are the three types of nuclear radiation?

Answer 3

Alpha, beta and gamma

Question 4

Each type of radiation has a different penetrative power, what does this mean?

Answer 4

The different radiations can pass through different thicknesses of materials

Question 5

What do alpha, beta and gamma radiations cause?

Answer 5

Ionisation

Question 6

What can ionisation do?

Answer 6

Damage healthy molecules in living cells, resulting in the death of the cell; this can lead to cancer

Question 7

What safety measures do people who handle radioactive materials need to take?

Answer 7

Wearing protective clothing, keeping their distance by using tongs to hold the material wherever possible, trying to minimise exposure time, and storing radioactive materials in clearly labelled and shielded containers.

Question 8

What can absorb alpha particles?

Answer 8

a few centimetres of air, or thin paper

Question 9

What can beta particles pass through, and what absorbs them?

Answer 9

They can pass through a few centimetres of air and thin paper, can be absorbed by a few centimetres of aluminium

Question 10

What can gamma rays pass through, and what stops them?

Answer 10

They can pass through a few centimetres of air, thin paper and a few centimetres of aluminium. Needs many centimetres of lead or metres of concrete to stop it

Question 11

What happens during ionisation?

Answer 11

A particle gains or loses electrons, leaving the atom charged

Question 12

What type of ion does a gain in electrons make?

Answer 12

A negative ion

Question 13

What type of ion does a loss of electrons make?

Answer 13

A positive ion

Question 14

Which alpha radiation emitting material does most smoke detectors contain?

Answer 14

Americium-241

Question 15

Why do most smoke detectors contain Americium-241, which emits alpha radiation?

Answer 15

The emitted alpha particles ionise air particles and the ions formed are attracted to the oppositely charged electrodes. This produces a current in the circuit. When smoke enters the space between the two electrodes, less ionisation takes place and an alarm is triggered

Question 16

What is a tracer?

Answer 16

A small amount of a radioactive substance that is put into a system so that its progress through the system can be followed using a radiation detector

Question 17

What can a beta emitter tracer be used to observe?

Answer 17

How elements such as nitrogen and phosphorus move through a plant, from root to leaf

Question 18

Why is beta radiation used in a paper thickness gauge?

Answer 18

Because when beta radiation passes through paper, some is absorbed. If the paper thickness is too great, more beta radiation is absorbed; less passes through to the detector. This indicates that the thickness of the paper needs to be reduced.

Question 19

Why can gamma radiation be used to treat cancer?

Answer 19

Because it destroys cancerous cells

Question 20

Why can gamma radiation be used to sterilise medical equipment?

Answer 20

Because it can destroy microorganisms like bacteria.

Question 21

How can non-destructive tests be carried out on welds?

Answer 21

By using gamma radiation. A gamma source is placed on one side of the material, and any cracks/defects are then seen using a detector on the other side.

Question 22

What happens to spent fuel?

Answer 22

It’s taken to be reprocessed

Question 23

How is low-level radioactive waste disposed of?

Answer 23

It’s sealed and buried in landfill sites

Question 24

How is high-level radioactive waste disposed of?

Answer 24

It’s enclosed in glass and stored underground in steel cylinders

Question 25

What are the four main problems with dealing with radioactive waste?

Answer 25

1) It remains radioactive for a long time, and must be disposed of safely. 2) It may be a target for terrorist activity. 3) It needs to be kept out of ground water to avoid contaminating drinking supplies. 4) The level of radioactivity that’s deemed to be acceptable may change over rime, so measures may need to be modified.

Question 26

Which type of radiation is the most penetrating?

Answer 26

Alpha

Question 27

Which 6 things is the universe made up of?

Answer 27

Planets, comets, meteors, stars, galaxies and black holes

Question 28

What are galaxies?

Answer 28

Large groups of stars

Question 29

What are black holes?

Answer 29

Dense, dying stars. They have a very large mass concentrated into a very small space; this is the reason why nothing can escape from them, not even light

Question 30

What is the centre of our solar system?

Answer 30

The sun

Question 31

What do satellites orbit?

Answer 31

The Earth

Question 32

How was the moon theorised to have formed/come to orbit the Earth?

Answer 32

By either giant impact, co-creation or capture

Question 33

What is the moon?

Answer 33

A natural satellite that orbits the Earth

Question 34

Why do planets, comets and satellites stay in their orbits?

Answer 34

Because the larger object exerts an inward pull force on them, which is provided by gravity

Question 35

What is centripetal force?

Answer 35

An inward pull force provided by gravity

Question 36

Name 3 problems with manned space missions

Answer 36

It can take months or years to reach planets, the fuel required takes up most of the spacecraft, room must be found to store enough food, water, and oxygen for the whole journey, a stable atmosphere must be maintained in the spacecraft, the temperature in space is freezing, so keeping warm is vitally important, outside of the Earth’s magnetic field, humans need shielding from cosmic rays, the low gravity affects people’s health, and radio signals tae a very long time to reach the Earth.

Question 37

Once landed on a planet, what about it can probes be used to send information back about?

Answer 37

temperature, magnetic field, radiation levels, gravity, atmosphere and surrounding landscape