Question
the half life of radium is 1620 year & its atomic weight is 226gm/mole. the number of atoms that will decay from its 1g sample per second is
1) 3.16 x 1010
2)3.6 x 1012
3) 3.1 x 1015
4) 31.1 x 1015
Joshi sir comment
for radioactivity we know that it is a first order process
so dN/dt = -λN
so dN/1 = -[0.6932/(1620*3.1*107)]*(1/226)*6.023*1023
solve now