From a radioactive substance `n_1` nuclei decay per second at an instant when total number of nuclei are `n_2`. Find half-life of the radioactive substance.

In a sample of a radioactive substance what fraction of the initial number of nuclei will remain undecayed after a time t =T/2 where T=half-life of radioactive substance.

The rate of disintegration of a radioactive substance falls from 800 decay//min to 100 decay//min in 6 hourse. The half life of the radioactive substance is :

A radioactive substance has 10^8 nuclei. Its half life is 30 s . The number of nuclei left after 15 s is nearly

A radioactive substance has 10^8 nuclei. Its half life is 30 s . The number of nuclei left after 15 s is nearly

N atoms of a radioactive substance emit n alpha -particles per second. The half life of the radioactive substance is

The activity of a radioactive substance is 4700 per minute. Five minute later the activity is 2700 per minute. Find (a) decay constant and (b) half-life of the radioactive substance.

State the law of radioactive decay and deduce an expression for half life of a radioactive substance.

A radioactive substance contains 10,000 nuclei and its half life period is 20 days. The number of nuclei present at the end of 10 days is

A radioactive substance contains 10, 000 nuclei and its half - life period is 20 days.The number of nuclei present at the end of 10 days is

There are two radioactive substances A and B. Decay constant of B is two times that of A. Initially both have equal numbr of nuclei. After n half lives of A, rate of disintegration of both are equal. Find the value of n.