Physics · May / June 2023 · Paper 12 · Question 36

A sample of a radioactive isotope with a very long half-life is placed next to a detector. Sheets of different materials are inserted, one at a time, between the radioactive sample and the detector. The background count rate is subtracted from the readings on the detector and the corrected count rates are recorded in the table. type of material | corrected count rate counts / s no sheet inserted | 450 thin aluminium sheet | 381 thin lead sheet | 285 thin paper sheet | 452 Which types of radiation are emitted by the radioactive sample?

1. Aalpha-particles and beta-particles only
2. Balpha-particles only
3. Cbeta-particles and gamma radiation only
4. Dgamma radiation only

As printed in the paper