JEE Mains · Physics · STD 12 - 13. Nuclei
A freshly prepared radioactive source of half life \(2\) hours \(30\) minutes emits radiation which is \(64\) times the permissible safe level. The minimum time, after which it would be possible to work safely with source, will be hours.
- A \(14\)
- B \(18\)
- C \(15\)
- D \(75\)
Answer & Solution
Correct Answer
(C) \(15\)
Step-by-step Solution
Detailed explanation
\(A = A _{0} \times 2^{- t / T }\) \(\frac{ A _{0}}{64}= A _{0} \times 2^{- t / T }\) \(\therefore t =6\,T =6 \times 2.5=15\,hours\)
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