Final answer:
The amount of tritium remaining after 48 years can be calculated using the formula: Remaining amount = Initial amount × (0.5)^(time elapsed / half-life).
Step-by-step explanation:
The question asks how much tritium will remain after 48 years given that the rock sample contains 20 mg of tritium. Tritium has a half-life of 12.3 years.
To calculate how much tritium will remain after 48 years, you can use the formula:
Remaining amount = Initial amount × (0.5)(time elapsed / half-life)
In this case, the initial amount is 20 mg, the time elapsed is 48 years, and the half-life is 12.3 years.
Substituting these values into the formula, we get:
Remaining amount = 20 mg × (0.5)(48 / 12.3)
Calculating this expression gives us the amount of tritium that will remain after 48 years.