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Question: Answered & Verified by Expert
The half-life of Au198 is 3 days. If atomic weight of Au198 is 198 g mol-1, then the activity of 2 mg of Au198 is [in disintegration second-1]:
PhysicsNuclear PhysicsJEE MainJEE Main 2021 (25 Jul Shift 1)
Options:
  • A 2.67×1012
  • B 6.06×1018
  • C 32.36×1012
  • D 16.18×1012
Solution:
1234 Upvotes Verified Answer
The correct answer is: 16.18×1012

A=λN

λ=ln2t1/2=ln23×24×60×60 sec-1=2.67×10-6 sec-1

N= Number of atoms in 2 mg Au

=2×10-3198×6×1023=6.06×1015

A=λN=1.618×1013=16.18×1012 dps

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