Questions in nuclei

Select	Question
	The activity of a sample is $64 \times 10^{–5}$ Ci. Its half-life is 3 days. The activity will become $5 \times 10^{–6}$ Ci after
	The half-life of radon is 3.8 days. Three forth of a radon sample decay in
	A nucleus of an element $_{84}{X^{202}}$ emits an $\alpha$ -particle first, a $\beta$ -particle next and then a gamma photon. The final nucleus formed has an atomic number
	3.8 days is the half-life period of a sample. After how many days, the sample will become 1/8th of the original substance
	Plutonium decays with a half-life of 24000 years. If the plutonium is stored for 72000 years, then the fraction of plutonium that remains is
	A radioactive substance emits
	The large scale destruction, that would be caused due to the use of nuclear weapons is called
	An atomic nucleus $_{90}T{h^{232}}$ emits several $\alpha$ and $\beta$ radiations and finally reduces to $_{82}P{b^{208}}$. It must have emitted
	In beta decay
	A radioactive substance has a half-life of 1 year. The fraction of this material, that would remain after 5 years will be