a little inquiry! PHY

[workinghard]

I wanted 2 inquire bout something :%)
Hopefully one f u ll b able 2 xplain it!
Da thing is dat in certain cases da ans given is rounded off and da further calc dat r done is based on that rounded fig and hence quite diff from da calc ones!
Lke in nov 09 41 q3b ii ans is 912.26 j/kg/K and da given ans is 910 j/kg/K
And da ans has got a mark 2
N like in same ppr ques 4 freq calc is 833.3 Hz and ans given is 830 Hz and a mark is allotted 2 da ans and all da following calc are based on dat 830 fig!
so can any1 kindly tell wat rule applies her? ardon:
I mean wen 2 round off or wen 2 leave it da wy it is cuz I don’t wanna lose any more marks den im goin 2 anywy!

 

[hassam]

hmm....the thing is that the final answer should be quoted to three sig. figure and the value used to calculate it should be carried forward on calculator ar 4-5 s.f of them shud be used....u mst not round them to 3 s.f and use rounded values to calculate final anser....hope that he;lps

 

[workinghard]

sory didn't get it really
wouldn't rounding off 2 3 sig fig of 912.26 be 912 ? n for 833.3 be 833???
if u can xpln again! plz!
thnx a million 4 tryn!

 

[hassam]

well those 2 ansers are to 2 sig figures,,,bt wat i am saying is that the calculation u perform to reaach final ans...in those steps u should not round......it cn lead to big error..either carry forward value in calculator or use 4-5 d.p

 

[workinghard]

oh thnx !