SP4e Dangers of radioactivity and background radiation

Question 1

Background radiation?

Answer 1

the ionising radiations we are constantly exposed to, at low levels.

Question 2

Radon?

Answer 2

.radon is emitted from rocks containing uranium compounds
.granite contains higher levels of these compounds

Question 3

How can radioactivity be detected?

Answer 3

.ionising radiation fogs/darkens photographic film and is used in film badges (dosimeters) to monitor exposure for people who work with radiation
.newer dosimeters no longer need to be photographically developed to see the dose, they simply change colour by different amounts depending on the exposure

Question 4

Geiger-Müller counters?

Answer 4

.they use Geiger-Müller tubes filled with an inert gas, like argon
.detect number of radioactive particles encountered per minute
.clicking is heard because of natural background radiation
.the more frequent the clicking heard the more particles detected

Question 5

Describe the dangers of exposure to radiation?

Answer 5

alpha, beta and gamma can enter living cells and collide with molecules. Collisions can cause ionisation, which damages or destroys molecules and can lead to tissue damage

Question 6

What do lower doses of radiation cause?

Answer 6

tend to cause mutations, cells with copying errors, which divide uncontrollably – this uncontrolled cell division is cancer

Question 7

What do high doses of radiation do and cause?

Answer 7

.kill cells completely, which causes radiation sickness
.this causes vomiting, tiredness, hair loss and could ultimately lead to death.

Question 8

How do the dangers of ionising radiation depend on half life?

Answer 8

.the lower the activity of a radioactive source, the safer it is
.if two sources start off with the same activity, the one with the longer half-life will always be more dangerous, because its activity falls off more slowly

Question 9

Irradiated?

Answer 9

.when someone is irradiated they are exposed to alpha, beta or gamma radiation from nearby radioactive materials
.the exposure stops when they move away

Question 10

Contaminated?

Answer 10

.you have been contaminated if you get particles of radioactive materials on, or inside your body
.you will be exposed as the unstable isotopes decay, and this will continue until the source is removed