The half-life of 65Zn is 245 days. After x days, 75% of original activity remained. The value of x i — JEE Mains Chemistry Past Papers Chemistry Question

💡 Solution & Explanation

1/2 n2 t K  n2 K  t a t n K a  25% 4 t n K  25% 4 t n n2 245  25% n 3 t n2  = 245 2log2 log3 log2        = 245 2 0.3010 – 0.4771 0.3010        = 101.66 day.