For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is :

20 10 15 30

20

No. of nuclei remaining = 600 - 450 = 150  \(\frac{N}{N_o}\) = (\(\frac{1}{2}\))1/t1/2 N = 150 ; No = 600 ;  t1/2= 10 minutes t = 2t1/2 = 20 minutes