RADIOACTIVITY
What is radioactivity?
Radioactivity is the spontaneous breakdown of unstable atomic nuclei, which releases radiation.
What is the atomic number of cobalt?
Answer: 27.
Why must Cobalt-60 treatment be carefully controlled?
Answer: Gamma radiation can damage both cancerous and healthy cells. Therefore, the radiation must be carefully controlled so that the cancer cells receive the required dose while exposure to healthy tissue is reduced.
State two safety precautions when handling radioactive materials.
Keep as far away from the source as possible and reduce the time spent near it. Shielding can also be used.
What type of radiation is mainly used from Cobalt-60 in medical treatment?
Answer: Gamma radiation.
Explain why Cobalt-60 can be used to sterilize medical equipment.
Answer: Gamma radiation can penetrate the equipment and destroy microorganisms such as bacteria by damaging their genetic material.
Name one detector that can be used to detect radiation.
A Geiger-Müller counter, also called a Geiger counter.
Why can Cobalt-60 be placed inside a sealed container while still being useful?
Answer: Gamma radiation can pass through the container, allowing the radiation to be used while reducing direct contact with the radioactive material.
Cobalt-60 is used in both cancer treatment and industrial testing. Explain how the same property of gamma radiation makes both applications possible.
Answer: Gamma radiation has high penetrating power. In cancer treatment, it allows radiation to enter the body and reach cancer cells. In industrial testing, it allows radiation to pass through thick materials so that internal defects can be detected.
State one difference between radioactive decay and a chemical reaction.
Radioactive decay involves changes in the nucleus of an atom, while chemical reactions involve changes in the arrangement of electrons.
What happens to the activity of a Cobalt-60 source as time passes?
Answer: Its activity decreases because more radioactive nuclei decay over time.
Explain why Cobalt-60 is useful for industrial testing even though the radiation itself cannot be seen.
Answer: Gamma radiation cannot be seen directly, but it can pass through materials and be detected using instruments. Differences in the amount of radiation reaching the detector can show changes inside the material, such as cracks, holes, or differences in thickness.
Why can’t radioactive decay be stopped by changing the temperature or pressure?
Radioactive decay occurs within the nucleus of the atom. Temperature and pressure mainly affect the electrons and chemical bonds, so they do not significantly affect nuclear decay.
A factory uses Cobalt-60 radiation to check for defects inside a metal component.
a) Why is gamma radiation suitable for this purpose?
Gamma radiation is suitable because it has high penetrating power, so it can pass through the metal component. If there is a defect, such as a crack or air space, the amount of radiation reaching the detector will change, allowing the defect to be detected.
A student claims that Cobalt-60 would be equally effective for industrial testing and cancer treatment if the radiation intensity were simply increased. Explain why this is not necessarily true.
Answer: Increasing the radiation intensity does not automatically make an application better. In cancer treatment, too much radiation can damage healthy cells. In industrial testing, too much radiation may be unnecessary and can increase the radiation exposure of workers. The radiation level must therefore be appropriate for the specific application.