65% of `.^111In` sample decays in 4.2 d.What is it half life?

A 3//4 of the original amount of radioisotope decays in 60 minutes.What is its half life?

0.5 g Sample of .^201TI decays to 0.07888 g in 8 days.What is its half life?

Decay constant of .^197Hg is 0.017 h^(-1) .What is its half life?

The gaseous reaction A_2 rarr 2A is first order in A_2 . After 12.3 minutes 65% of A_2 remains undecomposed. How long will it take to decompose 90% of A_2 ? What is the half life of the reaction?

Half life of .^18F is 110 minutes.What fraction of .^18F sample decays in 20 minutes?