The half-life of `Th^(232)` is `1.4xx10^(10)` years and that of its daughter element `Ra^(228)` is 7 years. Calculate the mass of `radium^(228)` in equilibrium with 1 g of `Th^(232)`.

The rth term of a G.P. is (-1)^(r-1).2^(r+1) , state the value of its 4th term :

The half-life of U^238 is 4.5xx10^9 y. In any radioactive sample if 1 g. of that element remains present then determine the activity of the sample in curie unit. (Avogadro number = 6.023xx10^23 ).

The decay constant for 6^(C^(14)) is 2.31xx 10^(-4) year-1 calculate the half life period.

Half-life of thorium is 1.5xx10^10 y. How much time is needed for 20% of thorium to disintegrate ?

The half-life of ._92^238U undergoing alpha -decay is 4.5xx10^9 year. What is the activity of 1 g. sample of ._92^238U ?

The half-life of At^215 is 100 mus .The time taken for the radioactivity of a sample of the element to decay 1/16 th of its initial value is

An element with density 11.2"g cm"^(-3) forms a fcc lattice with edge length of 4xx10^(-8) cm. Calculate the atomic mass of the element.

Calculate the mass of 1 mol of electrons if the mass of one electron be 9.11xx10^(-31)kg .

The half life of Th^(233) is 1.4 xx 10^(10) years. Calculate its disintegration constant. (i) 18Ar^(10) +____ rarr19^(k^(40))+0^(n^(1)) (ii) ________+ 1H^(1)rarr2^(He^(4))+2He^(4) (iii) 88Ra^(236)rarr ________+ 2^(He^(4)) (iv) 92^(U^(238))rarr56^(Ba^(143)) +_________+ 0^(n^(1))