NEET Physics Nuclei Questions Solved


The half-life of a radioactive substance against α-decay is 1.2×107 s. What is the decay rate for 4×1015 atoms of the substance
(a) 4.6×1012 atoms/s          (b) 2.3×1011 atoms/s
(c) 4.6×1010 atoms/s          (d) 2.3×108 atoms/s

(d) dNdt=-λNdNdt=0.693T1/2×N

=0.6931.2×107×4×1015=2.3×108 atoms/sec

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