Question

If the half life of Substance A is 0.5 years, how long would it take for 2 grams of substance A to remain given an initial mass of 16 grams?

Answer 1

Time taken is given by :

`t=-(1)/(k)([A_t])/([A_o])` .......( 1 )

Also,

`k = (0.693)/(t_(0.5))\\\\\\k=(0.693)/(0.5)\\\\k=2* 0.693\ year^(-1)`

Putting value of k in equation 1, we get :

`t=(1)/(2* 0.693)* ln((2)/(16))\\\\t=1.5\ years`

Therefore, time taken is 1.5 years.

Hence, this is the required solution.