Question

How much will be left after 24 hrs if it’s half life is 6 hours?

Answer 1

Hello there! A half-life is basically a decay of 50%. We will find the amount left after one day by exponential decay. The formula for exponential decay is A(1 - r)^t, where A = initial amount, r = rate (in decimal form), and t = time (or in this case, amount of half lives). The half-life is 6 hours and 24 goes into 6 four times. That's 4 half lives. Let's start by subtract 50% (0.5) from 1. 1 - 0.5 is 0.5. Now, we will use 0.5 and raise it to the 4th power, because the 4th power represents 4 half lives. 0.5^4 is 0.0625. Leave this number on the calculator. Do not round. Multiply that number by 448 to find the amount left. When you do, you get 28. There. 28 grams will be left after 24 hours.