Radioactivity – Revision Questions

  1. What 3 particles are all atoms made from?
     
  1. Whereabouts in an atom can one find each of these particles?
     
  1. About how many elements are there?
     
  1. What do all atoms of the same element have the same number of?
     
  1. What do we call atoms of the same element which have different numbers of neutrons?
     
  1. What will an unstable atom do at some point in the future?
     
  1. State 2 ways that nuclear radiation can be detected.
     
  1. Which type of radiation

a)      Can only travel a few cm in air?

b)      Can penetrate several cm of lead?

c)      Can get through paper easily but not thin metal?

  1. What is an alpha particle?
     
  1. What is a beta particle?
     
  1. What is gamma radiation?
     
  1. When is alpha radiation the most dangerous?
     
  1. Why do things which are radioactive give off less radiation as time goes by?
     
  1. What is the half life of the substance which produced the graph below?

15. A sample of Cobalt 60 produces 1000 counts per second. It has a half life of 5.3 years.

a)      What will the count rate be after 5.3 years?

b)      What will it be after 10.6 years?

16. To measure the thickness of the paper it produces a paper mill uses a substance that produces radiation.

a)      Why wouldn’t alpha or gamma radiation be suitable?

b)      Why is a substance with a half life of several years chosen?

17. To detect tumours inside a patients body they are injected with a substance that emits gamma radiation then scanned with a gamma camera.

a)      Why wouldn’t alpha or beta radiation be suitable?

b)      Why is a substance chosen that has a half life of a few hours?