IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: hira on June 08, 2010, 03:15:02 pm

Title: ABSOLUTE ERROR IN PHY P5
Post by: hira on June 08, 2010, 03:15:02 pm

please help me in finding the absolute error in physics P5

if a length is giving for eg 6 +- 0.4 ...find L^2 and its absolute erro

please help me please

Title: Re: ABSOLUTE ERROR IN PHY P5
Post by: falafail on June 08, 2010, 04:54:24 pm

you find the percentage error first then multiply by the value you get for L^2
here the percentage error is 2 X 0.4/6

Title: Re: ABSOLUTE ERROR IN PHY P5
Post by: Gaz on June 08, 2010, 05:05:11 pm

The question you are referring to is MJ07 P5 Q2b. It is done as follows:
- assume a value of 6+- 0.4. 
- square of 6 is 36.
- 6+0.4= 6.4.  square of 6.4= 40.96
- to find the error in the square, 40.96-36= 4.96
- hence the final answer to be recorded in the table is 36+- 5.0

Note that i put 5.0 instead of 4.96. The mark scheme allows a range of 4.6-5.0. You should use the same number of decimal places that the question uses.

Title: Re: ABSOLUTE ERROR IN PHY P5
Post by: wildrider on June 08, 2010, 05:27:16 pm

Quote from: hira on June 08, 2010, 03:15:02 pm

please help me in finding the absolute error in physics P5

if a length is giving for eg 6 +- 0.4 ...find L^2 and its absolute erro

please help me please

1st- 0.4/6*100=6.67%
2nd- 6.67*2=13.3%
3rd- 13.3*36/100= 4.8
->    36+-4.8