Bismuth has half life period of 5 days. A sample originally has a mass of $1000 \mathrm{mg}$, then the mass…

Bismuth has half life period of 5 days. A sample originally has a mass of $1000 \mathrm{mg}$, then the mass of Bismuth after 30 days is
  1. 16.625
  2. 13.625
  3. 14.625
  4. 15.625

Solution

Half life period of bismuth is 5 days. Initial mass $=1000 \mathrm{mg}$ $\therefore \quad$ Mass left after 5 days $=500 \mathrm{mg}$ Mass left after 10 days $=250 \mathrm{mg}$ Mass left after 15 days $=125 \mathrm{mg}$ Mass left after 20 days $=62.5 \mathrm{mg}$ Mass left after 25 days $=31.25 \mathrm{mg}$ Mass left after 30 days $=15.625 \mathrm{mg}$

Asked in: MHT CET 2021 (22 Sep Shift 1)

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