Question 1: Define irradiation in the context of radioactivity.

Answer: Irradiation is the exposure of an object or person to radiation from a radioactive source without direct contact with the radioactive material.

Question 2: Explain how contamination differs from irradiation in radioactive exposure.

Answer: Contamination involves radioactive particles settling on or inside an object or person, whereas irradiation involves exposure to radiation without particles attaching.

Question 3: List two safety precautions when handling radioactive materials to prevent contamination.

Answer: Wearing protective gloves and using remote handling tools.

Question 1: A radioactive source emits 5000 alpha particles per second. If a person is exposed to this source for 10 seconds, how many particles are they exposed to? Show your calculation.

Answer: Number of particles = emission rate x time = 5000 particles/sec x 10 sec = 50,000 particles.

Question 2: A contaminated surface has a measured radioactivity of 200 becquerels (Bq). How many decays occur in 30 seconds?

Answer: Decays = activity (Bq) x time = 200 decays/sec x 30 sec = 6000 decays.

Question 3: Interpret the following data: A worker is exposed to a radioactive source that causes a dose of 2 millisieverts (mSv) over 8 hours. Is this within safety limits? (Typical safety limit is 20 mSv/year).

Answer: Yes, because 2 mSv over 8 hours is well below the annual limit of 20 mSv.

Question 1: Describe a basic experiment to demonstrate the difference between irradiation and contamination using safe materials.

Answer: One possible experiment involves using a weak radioactive source and a Geiger counter to measure radiation exposure (irradiation) at a distance, versus placing radioactive particles on a surface and measuring contamination by wiping with a cloth. In both cases, safety precautions include wearing gloves, minimizing exposure time, and working behind shielding.

Question 2: Identify three variables that need to be controlled in experiments involving radioactive sources.

Answer: Distance from source, exposure time, and shielding material.

Question 1: A nuclear medicine department uses radioactive isotopes for diagnostic imaging. Explain how they prevent contamination and irradiation risks to patients and staff.

Answer: They use shielding to minimize irradiation, handle radioactive materials with remote tools, and ensure proper disposal of contaminated waste. Staff wear protective clothing and follow strict protocols to prevent contamination and unnecessary exposure.

Question 2: In everyday life, what precautions can people take to avoid contamination from radioactive sources found in certain industrial or medical devices?

Answer: Avoid direct contact with radioactive sources, follow safety instructions, and ensure proper disposal or shielding of radioactive materials.