WAEC - Physics (2004 - No. 49)
A radioactive substance has a half-life of 3 days. If a mass of 1.55g of this substance is left after decaying for 15 days, determine the original value of the mass
49.6g
37.2g
24.8g
12.4g
Explication
\(1 \to \frac{1}{2} \to \frac{1}{4} \to \frac{1}{8} \to \frac{1}{16} \to \frac{1}{32}\)
\(\frac{1}{32} = 1.55g\)
1 = 1.55 x \(\frac{32}{1} = 49.6g\)
\(\frac{1}{32} = 1.55g\)
1 = 1.55 x \(\frac{32}{1} = 49.6g\)