What is the function of a screw gauge in the experiment of determining Young's modulus of a wire?
Screw gauge is used to measure the diameter (d) of the wire so that the area of cross-section is calculated by the formula
A=πd24
In a Searle's experiment, the diameter of the wire as measured by a screw gauge with least count 0.001 cm is 0.050 cm. The length, measured by a scale of least count 0.1 cm, is 110.0 cm. When a weight of 50 N is suspended from the wire, the extension is measured to be 0.125 cm by a micrometer of least count 0.001 cm. Find the maximum error in the measurement of Young's modulus of the material of the wire from these data.
y=WA×LX