The activity of a nucleus is inversely proportional to its half of average life. Thus, shorter the half life of an element, greater is its radioactivity, i.e., greater the number of atomsd disintegrating per second. The relation between half life and average life is `t_(1//2) = (0.693)/(lambda) = tau xx 0.693`
or `tau = 1.44 t_(1//2)`
The half-life periods of four isotopes are given 1 = 6.7 years, II = 8000 years, III = 5760 years, `IV = 2.35 xx 10^(5)` years. Which of these is most stable?

Options

A. I
B. II
C. III
D. IV

Answer

d