Answer:
3 days
Explanation:
We have to use the formula;
N/No = (1/2)^ t/t1/2
Where;
N= amount of radioactive material left after a time t = 0.250g
No= original amount of radioactive substance present= 1g
t= time taken to decay to N= 6 days
t1/2= half life of the sample
N/No = (1/2)^ t/t1/2
Substituting values;
0.25/1 =( 1/2)^6/t1/2
25/100 = ( 1/2)^6/t1/2
1/4 = (1/2)6/t1/2
(1/2)^2 = (1/2)6/t1/2
Canceling out bases and equating powers
2= 6/t1/2
t1/2= 6/2
t1/2= 3 days
