Two radioactive substances have half-lives `T` and `2T`. Initially, they have equal number of nuclei. After time `t=4T`, the ratio of their number of nuclei is `x` and the ratio of their activity is `y`. Then,

Two radioactive substances A and B have half lives of T and 2T respectively. Samples of a and b contain equal number of nuclei initially. After a time 4T , the ratio of the number of undecayed nuclei of A to the number if undecayed nuclei of A to the number of undeacyed nuclei of B is

Half-life of a radioactive substance A and B are, respectively, 20 min and 40min . Initially, the samples of A and B have equal number of nuclei. After 80 min , the ratio of the ramaining number of A and B nuclei is

Half-lives of two radioactive substances A and B are respectively 20 minutes and 40 minutes. Initially, he sample of A and B have equal number of nuclei. After 80 minutes the ratio of the remaining number of A and B nuclei is :

Half-lives of two radioactive elements A and B are 20 minutes and 40 minutes respectively. Initially, the samples have equal number of nuclei. After 80 minutes, the ratio of decayed numbers of A and B nuclei will be :

Half-lives of two radioactive elements A and B are 20 minutes and 40 minutes respectively. Initially, the samples have equal number of nuclei. After 80 minutes, the ratio of decayed numbers of A and B nuclei will be

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) ?

Two radioactive materials X_1 and X_2 have decay constants 10 lamda and lamda respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X_1 to that of X_2 will be 1//e after a time.

Two radioactive materials A and B have decay constants 5lambda and lambda respectively. Initially both A and B have the same number of nuclei. The ratio of the number of nuclei of A to that of B will be 1/e , after the time x/(8lambda) then x is :