PHYSICS 244 . 
EXPERIMENT #5
 

Q.1.     Show that Eqn. (4) satisfies Eqn. (1).  

 

Q.2.     How would Eqns. (9) and (10) change if we used loge 
instead of log10?  

 

Q.3.     If 40% of an unstable substance remained after 10 hours, what
is the half-life of that substance?  

 

Q. 4.    What is the probability that a single nucleus which still
remains in the sample from Q.3 will decay within the next 1 hour?  

 

Q.5.     There are two decay processes in a sample, a primary one with
a half-life of 5 minutes and a residual one of 30 counts per 30 sec
which is essentially constant over the lab period.  The initial number
of counts is 300 per 30 sec.  
What is the apparent half-life of the primary decay
process if we fail to correct for the contamination?  

I guess the Q5 assumes the initial count 300 in 30 seconds, which is
not explicitly stated but implicitly used in the lab manual.

if so, primary count is only 300-30 counts in 30 sec, i.e. 270 counts
in 30 sec.

If 270 primary count give the half-life 5 min,
then 300 apparent count give the mistaken half-life of 4.5 min.

p.s. I still believe the question is confusing, so we can skip it.