Introduction
The object or the significant and the purpose of this report is to give the laboratory findings on the relative accuracy and application of different measuring devices for linear measurement . the problem is that we really not sure which of this devices ( steel ruler,varnier,micrometer ) is really suitable for measuring diameter and length . our investigation was to find out which one is very much accurate in the measuring diameter and which is much accurate in measuring the length so that in all our application we can identify which one contains errors and which one is accurate
Though all instrument can be used when measuring but they all differ an accuracy and error. For part 2 we were comparing the accuracy which may be achieved in comparing two slightly different lengths using an autocollimating telescope , a sigma comparator and a mercer comparator
Objective
To study the relative accuracy and application of different measuring devices for linear measurement
Method
A cylindrical sample of silver steel was supplied the length and diameter of the sample were measured using the following apparatus
- Steel ruler
- Verner
(SEE FIGURE 2)
- Micrometer
(SEE FIGURE 1)
- Slip gauges and sigma comparator
- Slip gauges and mercer comparator
Results
Table A (20mm sample & 20mm slip gauge to zero sigma comperator)
Sigma deviation = -0.08 mm
Table B (51mm length & 51mm slip gauge height to zero sigma comperator)
Sigma deviation = -0.06 mm
Comparing both tables:
Skel ruler measure the length more accurately
Vernier measures the length accurately & errors in diameter
Micrometer measures the diameter accurately and the layer length
Discussions
All the above instruments are used to measure in mm but due to the shortcoming in accuracy their accuracy level differ depending on what to be measured i.e heigth or diameter and how small is that to be measured
Conclusion
The relative accuracy differ from instrument and mostly depending on the application and for this instrument the vernier gave the accuracy when measuring length and the micrometer the high accuracy when measuring diameter and the skel ruler nearly measure the length accurately but it seems it can measure both diameter and length in exactly the same level of accuracy
Part 2
Objective
To compose the accuracy which may be achieved in comparing two slightly different lengths using an autocollimating telescope a sigma comparator and a mercer comperator
Analysis of reading from an autollimator