What is half life period.

The decay constant for 6^(C^(14)) is 2.31xx 10^(-4) year-1 calculate the half life period.

Show that for a first order reaction the time required for 99.9% completion is about 10 times its half life period.

One ml of methyl acetate was added to 20 ml of 0.5 N sulphuric acid. 2 ml of the reaction mixture was with drawn at various time intervals and titrated against a solution of standard alkali. The titre values are tabulated. Show that the reaction is first order and calculate the rate constant and half life period of the reaction.

A radioactive element has half-life period of 30 days. How much of it will be left after 90 days?

Find out the half life period of ""_(6)^(14) C whose decay constant is 2.25 xx 10^(-4) year ""^(-1)