A radioactive substnce havig N nuclei has activity R.Write down an expressin for its half-life in terms of R and N.

A radioactive substance decays to 1//32 th initial activity in 25 days.Calculate its half life.

One gram of _(88) Ra^(226) has activity of one curie .Find its half-life period.

A sample of a radioactive isotope contains N nuclei at time t.At time (t+triangle t) ,it contains (N-triangleN) nuclei of the isotope. For the period trianglet ,state in terms of N,triangle N and trianglet , the mean activity of the sample

A sample of a radioactive isotope contains N nuclei at time t.At time (t+triangle t) ,it contains (N-triangleN) nuclei of the isotope. For the period trianglet ,state in terms of N,triangle N and trianglet , the probability of decay of a nucleus.

Radioactive disintegration is a first order reaction and its rate depends only upon the nature of nucleus and does not depend upon external factors like temperature and pressure. The rate of radioactive disintegration (Activity) is represented as -(dN)/(dt)=lambdaN Where lambda= decay constant, N= number of nuclei at time t, N_(0) =intial no. of nuclei. The above equation after integration can be represented as lambda=(2.303)/(t)log((N_(0))/(N)) Calculate the half-life period of a radioactive element which remains only 1//16 of its original amount in 4740 years: a) 1185 years b) 2370 years c) 52.5 years d) none of these

A radioactive nuclide is produced at a constant rate of alpha per second . It’s decay constant is lambda . If N_(0) be the no. of nuclei at time t=0 , then max. no. nuclei possible are : a) N_(0) b) alpha//lambda c) N_(0)+(alpha)/(lambda) d) (lambda)/(sigma)+N_(0)s

Radioactive disintegration is a first order reaction and its rate depends only upon the nature of nucleus and does not depend upon external factors like temperature and pressure. The rate of radioactive disintegration (Activity) is represented as -(dN)/(dt)=lambdaN Where lambda= decay constant, N= number of nuclei at time t, N_(0) =initial no. of nuclei. The above equation after integration can be represented as lambda=(2.303)/(t)log((N_(0))/(N)) Half-life period of U is 2.5xx10^(5) years. In how much time will the amount of U^(237) remaining be only 25% of the original amount ? a) 2.5xx10^(5) year b) 1.25xx10^(5) years c) 5xx10^(5) years d) none of these