The half - life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is
- (A)1.042 g
- (B)4.167 g
- (C)3.125 g✓ Correct
- (D)2.084 g
Answer: (C)
Solution
With a four-hour half-life, the hours cover half-lives. After half-lives the surviving mass is the starting amount divided by , so here it is left undecayed.
JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option