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error bars physics p5

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aldehyde1612:
Its the fractional uncertainty in V0 + fractional uncertainty in I0 ...then multiply that by your Xc value.
you add them because to get Xc you divided V/I ... or something along those lines. Maybe try that and see if you get the answer.  :D

winnie101:
nope, still not working.
this is what is did:
for the first row (0.2/5)+(0.2/0.015)=13.373
then if u multiply this value by value of Xc which is 333, it gives a very large number, 4453.32, whereas the ans is 12
if u could help further id greatly appreciate it
Thanks

aldehyde1612:
Are you sure the answers 12?? .. cause I got 16.7?

where you went wrong is (0.2/0.015)   ..... It should be (0.2/15) cause the x10-3 applies to the error (0.2) as well, so it cancels out when you're dividing.
But with that I get 0.05.. so multiplied by 333 is 16.65? :-\

TJ-56:

--- Quote from: aldehyde1612 on May 22, 2011, 11:48:19 am ---Are you sure the answers 12?? .. cause I got 16.7?

where you went wrong is (0.2/0.015)   ..... It should be (0.2/15) cause the x10-3 applies to the error (0.2) as well, so it cancels out when you're dividing.
But with that I get 0.05.. so multiplied by 333 is 16.65? :-\

--- End quote ---

I believe your work is done correctly. The uncertainty for example in the first row = [ (0.2/5) + (0.2/15) ] * 333 ( or 5/15x10^-3 which is 333.33333... ) The answer exactly is 17.77778, which is written simply as 18.
Hope that helped.

winnie101:
woops, made another mistake reading the marking scheme, u guys are right
Thanks

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