Q18 / 150 · MHT CET 2007 · Chemistry

A certain nuclide has a half-life period of 30 min. If a sample containing 600 atoms is allowed to decay for 90 min, how many atoms will remain ?

  • A
    200 atoms
  • B
    450 atoms
  • Correct answer
    C
    75 atoms
  • D
    150 atoms

Solution

$\begin{aligned} n &=\frac{\text { total time }}{\text { half- life period }}=\frac{90}{30}=3 \\ N &=N_{0} \times\left(\frac{1}{2}\right)^{n} \\ &=600 \times\left(\frac{1}{2}\right)^{3} \\ &=\frac{600}{8} \\ &=75 \text { atoms } \end{aligned}$

Hence, the correct answer is option: 'C'.

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