Questions in nuclei

Select	Question
	Radon (Ra) decays into Polonium (${P_0}$) by emitting an $\alpha - $ particle with half-life of 4 days. A sample contains $6.4 \times {10^{10}}$atoms of$Rn$. After 12 days, the number of atoms of ${R_n}$left in the sample will be
	Decay constant of radium is$\lambda $. By a suitable process its compound radium bromide is obtained. The decay constant of radium bromide will be
	In the uranium radioactive series, the initial nucleus is $_{92}{U^{238}}$and the final nucleus is $_{82}P{b^{206}}$. When the uranium nucleus decays to lead, the number of $\alpha - $ particles emitted will be
	After $1\gamma$and $2\gamma$ emissions
	Which of the following is a correct statement
	$^{22}Ne$ nucleus after absorbing energy decays into two $\alpha - $ particles and an unknown nucleus. The unknown nucleus is
	Half lives of two radioactive substances A and B are respectively 20 minutes and 40 minutes. Initially the sample of A and B have equal number of nuclei. After 80 minutes, the ratio of remaining number of A and B nuclei is
	A nucleus $_n{X^m}$emits one $\gamma$ and one $\gamma$ particles. The resulting nucleus is
	If the radioactive decay constant of radium is $1.07 \times {10^{ - 4}}$per year, then its half life period is approximately equal to
	The half life of $^{131}I$is 8 days. Given a sample of $^{131}I$at time t = 0, we can assert that