Radioactive material 'A' has decay constant `'8 lamda'` and material 'B' has decay constant 'lamda'. Initial they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be `(1)/( e)` ?

Radioactive material 'A' has decay constant '8 lamda' and material 'B' has decay constant 'lamda'. Initial they have same number of nuclei. After what time, the ratio of number of nuclei of material 'A' to that 'B' will be '(1/ e) ?

Radioactive material 'A' has decay constant 8lambda and material 'B' has decay constant 'lambda' . Intially they have same number of nuclei . After what time the ratio of number 'B' to that 'A' will be 1/e .

Two radioactive materials A and B have decay constants 10lambda and lambda , respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of A of that of B will be 1//e after a time :

Two radioactive material A and B have decay constants 10 lambda and lambda , respectively. If initially they have a the same number of nuclei, then the ratio of the number of nuclei of A to that of B will be 1//e after a time 1/(n lambda) , where n is ___________