Questions in nuclei

Select	Question
	The half-life of $B{i^{210}}$is 5 days. What time is taken by (7/8)th part of the sample to decay
	A radioactive nucleus undergoes a series of decay according to the scheme $A \xrightarrow{\alpha}A_1 \xrightarrow{\beta}A_2 \xrightarrow{\alpha}A_3 \xrightarrow{\gamma}A_4$ If the mass number and atomic number of A are 180 and 72 respectively, then what are these number for A4
	Radioactivity is
	Half life of radioactive element depends upon
	The decay constant of radium is $4.28 \times {10^{ - 4}}$per year. Its half life will be
	Which of the following is not a mode of radioactive decay
	Atomic mass number of an element thorium is 232 and its atomic number is 90. The end product of this radioactive element is an isotope of lead (atomic mass 208 and atomic number 82). The number of alpha and beta particles emitted is
	A sample contains 16 gm of a radioactive material, the half life of which is two days. After 32 days, the amount of radioactive material left in the sample is
	A radio-isotope has a half- life of 5 years. The fraction of the atoms of this material that would decay in 15 years will be
	Curie is a unit of