Need help with this half life question

Question

The first-order rate constant for the decay of Cs-137 is 6.3 x 10^-5d^-1(read: per day). Determine the time, in years, that corresponds to one (1) half-life. (1 y = 365 d)

Answer 1

Hello Divine

 

t_1/2 = 0.693 / k

 

t_1/2 = 0.693 /  6.3 x 10^-5 d^-1

 

       = 11,000 days

 

Time in years =

 

11,000 days x (1 year / 365 days) = 30 years