tough question !

[yousef]

hello everybody .......... i really tried to solve 2 questions .. (one from chem ) and one from (physics) and it made me go crazy !


so any HELP PLZ ????
chem ....... http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s03_qp_2.pdf QN __1

phy...........http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf QN __5 >> last part for no. of minima

 

[scouserlfc]

here i answered in chem thread for chemistry i guess u forgot this alert or something or the other !

Here it goes !
Isotope definition is supposed to be written here refer to your books or use your brain or maybe just write an atom with same electrons and protons but different number of neutrons

for peak at 35 35Cl is responsible for it
for peak at 38 ,H and 37 Cl are responsible that is HCl (with Cls nucleons = 37 )

As it tells u to look at the peaks to decide the ratio of the two Cl isotopes then look at the peaks at 35 and 37 only as they contain Cl only
the relative abundance of 35 peak is about 30 and for the peak at 37 it is abt 10
now just do this
35Cl : 37Cl
30 : 10
3 : 1
so thats the ratio !

so we know that they exist in the ratio 3:1 so now use the idea that these isotopes are the only Cl isotopes so their total abundance equals to as seen in the graph 40 and do this working
((3(35) + 1(37))/40) * 100
35.5 is the answer !

 

[scouserlfc]

and for the physics one i also require it to be solved by someone good in it