Homework Help: A Disintegration Problem

1. Feb 1, 2013

Hysteria X

1. The problem statement, all variables and given/known data

In a chain radioactive disintegration,the half-life of the parent and daughter nuclide are 10 years and 25 years respectively.if the disintegration process is at its equilibrium stage with the parent no. of nuclei equal to 5* 10^8, the daughter no. of nuclei will be

2. Relevant equations
t1/2 = 0.639/λ

n/n0=(1/2)^(t/(t1/2))

n/n0=$e^-λt$
3. The attempt at a solution

t11/2 = 10 years
t21/2 = 25 years
N=No (because its at equilibrium)
→e^-tλ=1
tλ=0??

2. Feb 1, 2013

clamtrox

I would imagine that the processes being in equilibrium means that the number of daughter nuclei that decay is equal to the number of parent nuclei that decay. Can you write an equation from this condition?

3. Feb 1, 2013

Hysteria X

yes thats what i have writtern n=n0 ?? initial number of nucleus ie parent nuclei = n0 and final number of nuclei ie daughter nuclei=n?
or should i take all together two different equations?

4. Feb 1, 2013

clamtrox

No, that's not correct. What's the number of nuclei that decay in a given time?