Applications of radioactivity - IB

Which of these is not a use radioactive isotopes.

• Carbon dating

• Smoke detectors

• Radar technologies

• Radiotherapy

Which of these statements is incorrect for Beta decay

• Is used to maintain the thickness of aluminium foil

• Is the most penetrating form of radiation

• Is the most ionising form of radiation

• Are effected by magnetic and electric fields.

Carbon dating is highly reliable for estimating the age of which of the below samples

• 5 years

• 300 years

• 40000 years

• 100000 years

Why is radioactivity used in food irradiation

• To add nutrients to food

• To eliminate bacteria and extend shelf life

• To improve the taste of food

• To cook food more efficiently

Which of the following is a major challenge in managing radioactive waste?

• Lack of materials for storage containers

• High cost of disposal

• Difficulty in detecting radiation

• Long half-lives of some radioactive isotopes

Which statements are correct about the sources of uncertainty in the Carbon-14 decay curve used for radiocarbon dating?

A) If the sample is less than 500 years old the activity of the sample will be too high to measure small changes accurately

1. B) The level of production of carbon-14 in the atmosphere varies slightly with location.

3. c) If the sample is more than 60,000 years old, background radiation makes it impossible to distinguish between the remaining Carbon-14 and external sources of radiation.

• A,B and C

• A and B only

• B and C only

• B only

Which of the following conditions is necessary for using carbon-14 in radiocarbon dating?

• The ratio of carbon-14 to carbon-12 must be measurable.

• The sample must be older than 10,000 years.

• The sample must contain uranium-238.

• The carbon concentration in the atmosphere must be variable.

  
  

Gamma radiation is used to detect leaks in underground pipes because:

• It has the shortest half-life.

• It can penetrate several meters of ground.

• It is absorbed by alpha particles in the pipe.

• It is safe for technicians to handle without shielding.

  
  

When using beta radiation to control the thickness of materials, why must the radioactive source have a long half-life?

• To ensure the rollers remain at a constant pressure.

• To reduce the amount of radiation absorbed by the material.

• To allow the beta particles to penetrate thicker materials.

  
  

• To minimize the need for frequent replacement of the radioactive source.

Why is americium-241 suitable for use in smoke detectors?

• It has a long half-life, ensuring consistent activity over the detector’s lifetime.

• It emits beta radiation, which can penetrate the casing of the detector.

• It produces gamma radiation, which is detectable even in the presence of smoke.

• It creates ionisation by emitting neutrons that interact with oxygen molecules.