24. percentage error in n = 25.5 %
Hence 25.5% of value is 0.3 x 10-3
Hence the written as (1.1 + 0.3) x10-3 kgm-1s-1
25. The average of several diameter reading is taken : 1. To reduce the random error
2. The wire may not be perfectly circular.
26. See definition in lecture notes
27.See numerical answers provided
28. aii) Measure zero error and take zeror error into account to remove systematic error.
Measure the diameter several times by rotating the sphere. To remove random error .
b) Measure the volume of the mercury inside the capillary tube. The formula , density - mass/volume can be used to find the volume of mercury. The volume of the tube can thus be used to find the diameter if the length is known. The volume of a cylinder is used.
The uncertainty due to diameter measurement is (0.2 / 25 )x100 = 0.8%. This percentage is close to the diameter variation of 1%. Hence it is not possible to detect the changes in diameter. See pic of travelling microscope.
29. Parallax error exist as the specimen (metal cylinder) is a distance away from the ruler. To reduce this error , use a set square to point at the ruler (touching the ruler scale reading ).
See how a traveling microscope works.
Look into microscope and read the reading R1 (vernier scale) . Move the microscope by turning the knob which moves the microscope to read R2. The length moved by the microscope is R1-R2. Hence the diameter of the capillary tube can be measured.
