Questions in nuclei

Select	Question
	A radioactive material has an initial amount 16 gm. After 120 days it reduces to 1 gm, then the half-life of radioactive material is
	Half-life of a substance is 10 years. In what time, it becomes $\frac{1}{4}$th part of the initial amount
	If ${N_0}$ is the original mass of the substance of half life period ${T_{1/2}} = 5$ years, then the amount of substance left after 15 years is
	The equation $_z{X^A}\, \to {\,_{z + 1}}{Y^A}{ + _{ - 1}}{e^0} + \bar v$ is
	The ratio activity of an element becomes 1/64th of its original value in 60 sec. Then the half life period is
	A radioactive substance emits
	If $_{92}{U^{238}}$ undergoes successively 8 $\alpha$ -decays and 6 $\beta$ -decays, then resulting nucleus is
	The activity of a sample of a radioactive material is A, at time ${t_1}$ and ${A_2}$ at time ${t_2}$ $({t_2} > {t_1}).$ If its mean life is T, then
	Nucleus produced due to $\alpha$ -decay of the nucleus $_Z{X^A}$ is
	When $_{90}T{h^{228}}$ transforms to $_{83}B{i^{212}}$, then the number of the emitted $\alpha$ - and $\beta$ -particles is, respectively