If t is the time required for a radioactive substance to reduce to one third of its initial amount, what fraction would be left over after0.5 t
1√3
t=1λInN0N=1λin113=1λIn 3 ....(i)
and 0.5t=1λIn1x (x fraction left) .....(ii)
From (i) and (ii) x=1√3