Physics · Composition and size of nucleus, atomic masses, mass-energy relation, mass defect

A radioactive substance of half life 69.3 days is kept in a container. The time

A radioactive substance of half life 69.3 days is kept in a container. The time in which \( 80 \% \) of the substance will disintegrate will be

  • A. 1.61 days
  • B. 16.1days
  • C. 161 days
  • D. 1610 days

Step-by-step solution

Using the decay formula: remaining fraction = 0.2 = (1/2)^(t/69.3). Solving for t: t = 69.3 * ln(0.2)/ln(0.5) ≈ 69.3 * 2.3219 ≈ 161 days.
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