Fisika Inti • Part 5: Aktivitas dan Peluruhan Inti Radioaktif (Radioaktivitas)

Introduction

This tutorial covers the concepts of radioactivity, focusing on the activity and decay of radioactive nuclei. Understanding these principles is essential in fields such as physics, geology, and archaeology, especially when estimating the age of fossils through radioactive decay.

Step 1: Understand Radioactive Activity

• Definition: Radioactive activity refers to the rate at which unstable atomic nuclei decay, releasing radiation.
• Key Factors:
  • The decay constant (λ), which indicates the probability of decay per unit time.
  • The number of remaining radioactive nuclei (N).

Practical Tip

• The relationship between activity (A), decay constant, and the number of nuclei can be expressed as:
  • A = λN
• Knowing this formula helps in calculating the activity of a radioactive sample.

Step 2: Learn About Half-Life

• Definition: Half-life is the time required for half the quantity of a radioactive substance to decay.
• Key Relationship:
  • The half-life (t½) is inversely related to the decay constant:
    • t½ = ln(2) / λ
• This means that the larger the decay constant, the shorter the half-life.

Practical Application

• Use half-life to determine the age of fossils or archaeological finds. By measuring the remaining radioactive material and knowing its half-life, you can estimate how long it has been decaying.

Step 3: Apply the Concepts with Examples

• Example Problem: Estimate the age of a fossil using its half-life.
  • Identify the radioactive isotope present in the fossil.
  • Determine its half-life.
  • Measure the remaining amount of the isotope.
  • Use the formula:
    • Age = (t½ * log2(N0/N))
      • N0 = initial quantity
      • N = remaining quantity

Common Pitfalls to Avoid

• Ensure accurate measurements of the remaining isotopes, as errors can lead to incorrect age estimations.
• Remember that different isotopes have different half-lives, so make sure to use the correct one for your calculations.

Conclusion

In this tutorial, we explored the concepts of radioactive activity and half-life, highlighting their importance in estimating the age of fossils. You can apply these principles in various scientific fields. For further learning, consider exploring additional parts of the series on nuclear physics for a more comprehensive understanding.