P4f-uses Of Radioisotopes

Question 1

Where does background radiation come from?

Answer 1

• Radon gas
• Rocks and building materials
• Medical x rays
• Food
• Cosmic rays
• The nuclear industry

Question 2

What are tracers used for in the industry?

Answer 2

• to track dispersal of waste
• to find leaks/blockages in underground pipes
• to find the route of underground pipes

Question 3

How are tracers used in industry?

Answer 3

1) radioactive material put into pipe
2) progress tracked with detector outside pipe
3) if the radioactivity stops/reduces there is a leak/blockage

Question 4

Why is gamma radiation used for tracers?

Answer 4

So that radiation can be detected through metal or earth surrounding the pipe

Question 5

How does a smoke detector work?

Answer 5

• weak alpha radioactive source in detector, close to two electrodes
• source ionises air particles, allowing current to flow
• if theres a fire, smoke particles are hit by alpha radiation
• less ionisation of air particles
• current is reduced causing alarm to sound

Question 6

How have the measurements of the activity of radioactive carbon lead to an approximate age for different materials?

Answer 6

• amount of carbon 14 in air has not changed for 1000 years
• when an object dies, gaseous exchange with the air stops
• as carbon 14 in wood decays, activity of sample decreases
• ratio of current activity from living matter to activity of sample is used to calculate the age