Questions in nuclei

Select	Question
	A radioactive sample with a half life of 1 month has the label : “Activity=2 micro curies on 1.8.1991.'' What will be its activity two months later
	An element A decays into element C by a two step process : $A \to B + {\;_2}H{e^4}$ $B \to C + \;2{e^ - }$ Then
	At any instant the ratio of the amount of radioactive substances 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
	Which of the following isotopes is used for the treatment of cancer
	If half-life of a radioactive atom is 2.3 days, then its decay constant would be
	A radioactive element $_{90}{X^{238}}$decay into$_{83}{Y^{222}}$. The number of $\beta -$ particles emitted are
	A radio isotope has a half life of 75 years. The fraction of the atoms of this material that would decay in 150 years will be
	The activity of a radioactive sample is measured as 9750 counts per minute at t = 0 and as 975 counts per minute at t = 5 minutes. The decay constant is approximately
	An artificial radioactive decay series begins with unstable $_{94}^{241}Pu$. The stable nuclide obtained after eight $\alpha -$ decays and five $\beta -$ decays is
	Consider the following two statements A. Energy spectrum of $\alpha$ -particles emitted in radioactive decay is discrete B. Energy spectrum of $\beta$ -particles emitted in radioactive decay is continuous