FOCUS ON: Calculating Half-lives (HIGHER)

Part 1 - Keywords:

1. Half-life

2. Radioactive decay

3. Isotope

4. Decay constant

5. Exponential decay

6. Radioactive emission

Part 2 - Key Facts:

1. Half-life is the time taken for the number of radioactive nuclei in a sample to halve.

2. Radioactive decay is a random process where unstable atomic nuclei lose energy by emitting radiation.

3. Isotopes are atoms of the same element with different numbers of neutrons and may have different half-lives.

4. The decay constant is a measure of how quickly a radioactive substance decays and is inversely proportional to the half-life.

5. Radioactive decay follows an exponential decay curve, meaning the rate of decay decreases over time.

6. Radioactive emissions include alpha particles, beta particles, and gamma rays, each with distinct properties and penetration abilities.

Part 3 - Quick Quiz:

1. What is half-life?

   a) Time taken for a radioactive substance to decay completely

   b) Time taken for the number of radioactive nuclei in a sample to halve c) Time taken for a radioactive substance to become stable

   Answer: b) Time taken for the number of radioactive nuclei in a sample to halve

2. Which of the following is NOT a radioactive emission?

   a) Alpha particle

   b) Beta particle

   c) Electron

   Answer: c) Electron

3. How does the decay constant relate to the half-life of a radioactive substance?

   a) They are directly proportional

   b) They are inversely proportional

   c) They are not related

   Answer: b) They are inversely proportional

Part 4 - Going Further:

Question: How can you calculate the net decline, expressed as a ratio, in a radioactive emission after a given number of half-lives?

Answer: To calculate the net decline in a radioactive emission after a certain number of half-lives, you can use the formula:

Net decline ratio=(1/2​)ⁿ

Where n is the number of half-lives elapsed. For example, if n=3, the net decline ratio would be (1/2)³=1/8.

Part 5 - Revision Tips:

Practice solving problems involving half-life calculations using different radioactive isotopes to become familiar with the concept and its application.

Part 6 - More Help:

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