The masses of two radioactive substance are same and their half lives are 1 hr and 2yr respectively. The ratio of their activities after 4yr will be:

Q. The masses of two radioactive substances are same and their half lives are $1$ year and $2$ years respectively. The ratio of their activities after six years will be

Q. The nuclei of two radioactive isotopes of same substance $A^{236}$ and $A^{234}$ are present in the ratio 4 : 1 in an ore obtained from Mars. Their half lives are $30\text{min}$ and $60\text{min}$ respectively. Both isotopes are alpha emitters and the activity of the isotope with half life $30\text{min}$ is one Rutherford. Calculate after how much time (in min) their activities will become identical.

Q. The nuclei of two radioactive isotopes of same substance $A^{236}$ and $A^{234}$ are present in the ratio of $4:1$ in an ore obtained from some other planet. Their half lives are $30\text{min}$ and $60\text{min}$ respectively. Both isotopes are $\text{alpha}$ emitters and the activity of isotope with half life $30\text{min}$ is ${10}^6\text{dps}$. Calculate after how much time their activities will become identical.

Q. Two radioactive substances $X$ and $Y$ initially contain an equal number of atoms. Their half-lives are $1$ hour and $2$ hours respectively. Then the ratio of their rates of disintegration after two hours is.

Q.

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 substance