This was because the wire was coiled originally and so kept trying to go back to its original coiled state. This means my wire length will be inaccurate to approximately half a millimetre. This would not have affected the permanent length of the wire because the wire enters the plastic region only after around 10 Newtons (Represented on a graph of axis force against extension) The slip mentioned in the results refers to how much the wire has been pulled from the two markers, which is referred to in the method. The slip is evidently not part of the extension and will be taken into account.
Original Length of the Wire = 3570mm. = 3. 57 meters Original Diameter of the wire = 0. 175mm = 1. 75 x 10-4 meters. Area = 0. 0000000962m3 = 6. 92 x 10-8m3 These results may be unduly accurate and this will be taken into account in the conclusion. As the Youngs Modulus concerns the region where Hookes Law is obeyed, then this will be the region where the extension increases in small equal amounts. In this case it is 1-9 Newtons here. As this only caused small extensions of 1mm per each weight added, this is where the biggest errors will occur.
Ruler to half millimetre accuracy 0. 5mm in 8mm = 0.5 / 8 100 = 6. 25% CONCLUSION What is Youngs Modulus Of Elasticity for Nicrome Wire? Youngs Modulus For Elasticity is defined as Stress Over Strain. So (Force Length) (Extension Cross-sectional Area).
This is the gradient of a graph representing stress over strain. (In the region where Hookes Law is obeyed) Force (N) Stress (Pa) Extension (m) Strain (Pascals) Youngs Modulus (Giga Pascals) The gradient of the graph represent the stress over the strain. The gradient over the ? y/? x region is big enough to provide a good average. It is more accurate than the tabulated result because it contains the linear y=mx+c graph (This is due to Hooks Law) which is the line of best fit for the results (The average).
The y-intercept on the graph is very close to the origin, which is what would be expected because if there were no stress (e. g. no force acting on the wire) then there would be, by definition, no strain, as there would be no extension occurring. This shows that this area is obeying Hooks Law because using the y=mx+c equation, this would say c i?? 0 (approximately equal to 0). So y=mx where tis the stress, x is the strain, and m is the constant; being Youngs Modulus. Conclusion:
My results are accurate, because the graph was a very straight line, as all the points could be plotted to a good degree of accuracy to the original plot from the y=mx equation; Stress = (5. 52 x 1011 ) x Strain :-> Where 5. 52 x 1011 Gpa is my result for Youngs Modulus for Nichrome Wire Stress (Pa) Strain Stress=(5. 52 x 10^11) x Strain Error From Original Dividing the result of multiplying the stress by my Youngs Modulus by the original, and multiplying by 100 calculated the error from original column.
For every multiplication I got a a result of 6. 72%, which is close to my approximate error range of 6%. My results compared to my prediction: My results, did not entirely agree with my prediction. From preliminary experiments the Youngs Modulus would be in the region of 180 GPa.