NEET Physics Nuclei Questions Solved


The half life of radium is 1620 years and its atomic weight is 226 kgm per kilomol. The number of atoms that will decay from its 1 gm sample per second will be

(a) 3.61×1010     (b) 3.6×1012
(c) 3.11×1015     (d) 31.1×1015

(Avogardo's number N = 6.02×1026 atpm/kilomol)

(a) 

dNdt=λN; λ=0.6931t1/2=0.69311620×365×24×60×60N=6.023×1023226

dNdt=0.6931×6.023×10231620×365×24×60×60×226=3.61×1010

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