Radioactive decay and types of radiationIB MYP Physics: Mind map

Exam questions on Radioactive decay and types of radiation

1. A hospital physicist in Manchester stores three radioactive sources, one that emits alpha particles, one that emits beta particles and one that emits gamma rays. She must choose suitable shielding for each source and check which types of radiation are most harmful to living cells.
   Compare the ionising power and the penetrating power of alpha particles and gamma rays.2 marks
2. Uranium-238 has atomic number 92. Its nuclei are unstable. A uranium-238 nucleus decays by emitting an alpha particle and forms a nucleus of thorium (symbol Th). The thorium-234 nucleus then decays by beta emission to form protactinium (symbol Pa).
   State the mass number and the atomic number of the thorium nucleus formed when uranium-238 decays by alpha emission.2 marks
3. A student investigates how well two materials absorb gamma radiation. She holds a Geiger-Muller tube 10 cm from a gamma source and records the number of counts in 60 seconds. With the source removed she records a background count of 12 in 60 seconds. With nothing between the source and the tube she records 612 counts. With a 5 mm sheet of aluminium in the way she records 598 counts, and with a 5 mm sheet of lead in the way she records 214 counts.
   Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks