Two radioactive nuclei X and Y initially contain an equal number of atoms.Their half life is 1 hour and 2 hours respectively.Calculate ratio of their rates of disintegration after two hours.

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.

In the chemical analysis of a rock the mass ratio of two radioactive isotopes is found to be 100:1. The mean lives of the two isotopes are 4xx10^9 years and 2xx10^9 years, respectively. If it is assumed that at the time of formation the atoms of both the isotopes were in equal propotional, calculate the age of the rock. Ratio of the atomic weights of the two isotopes is 1.02:1.

A fresh radioactive mixture contians short lived sppecies A and B. Both emitting alpha -particles intially of 8000 alpha particles per minute. 20 minutes later, they emis at the rate of 3500 alpha -particles per minute. If the half-lives of the species A and B are 10 minutes and 500 hours respectively, then the ratio of activities of A: B the intial mixture was:

The oxidation potential of two metals X and Y are +2.37 and +1.66 V respectively. In a chemical reaction:

Two different radioactive elements with half-lives T_1 and T_2 and N_1 and N_2 (undecayed) atoms respectively present at a given instant. Determine the ratio of their activities at this instant.

Two nuclei have mass number in the ratio of 1:2, what is the ratio of their nuclear densities?

Two particles of equal masses are revolving in circular paths of radii r_1 and r_2 respectively with the same time period .The ratio fo the centripetal force is :

Two flask A and B of equal volumes maintained at temperature 300K and 700K contain equal mass of He(g) and N_(2)(g) respectively. What is the ratio of total translational kinetic energy of gas in flask A to that of flask B ?

At any instant, the ratio of the amount of radioactive substance is 2:1. If their half lives be respectively 12 and 16 hours, then after two days what will be the ratio of the substances?

In a culture, the bacteria count is 1,00,000. The number is increased by 10% in 2 hours. In how many hours will the count reach 2,00,000, if the rate of growth of bacteria is proportional to the number present?