When the nuclei in certain atoms undergo radioactive decay, they emit one or more types of radiation – alpha, beta and gamma - Leaving Cert Physics - Question d - 2020

To compare the penetrating power of alpha, beta, and gamma radiation, the following experimental setup can be used:

Apparatus:

• Radioactive sources (like Americium-241 for alpha, Strontium-90 for beta, and Cobalt-60 for gamma)
• Barriers of different materials (e.g., paper, aluminum, lead)
• Detector or Geiger-Müller (GM) tube

Procedure:

1. Set up the radioactive sources at a fixed distance from the detector.
2. Place various barriers between the source and the detector one at a time. Start with a paper barrier for alpha radiation, then foil for beta, and a lead sheet for gamma.
3. Measure the count rate recorded by the detector with and without each barrier present.

Observation/Conclusion:

• Alpha particles will be stopped first by paper.
• Beta particles penetrate aluminum but not lead.
• Gamma rays penetrate all materials the best, demonstrating their greater penetrating power.

To calculate the atomic number A of the unknown element X, we need to use the conservation of atomic numbers:

• Given that Rn has an atomic number of 86 and it loses an alpha particle (which has an atomic number of 2), you calculate:

  A = 86 - 2 = 84.

To calculate the mass number Z, we apply the conservation of mass numbers:

• The mass number of radon is 220. An alpha particle has a mass number of 4. Therefore, we calculate:

  Z = 220 - 4 = 216.

Element X is Polonium, which is represented by the symbol Po.

One use of nuclear radiation is in sterilizing medical equipment, where radiation effectively eliminates bacteria and viruses.