Answer the following questions related to errors and significant figures:
a. (i) Define absolute error, relative error and percentage error in the measurement of a physical quantity.
b. (ii) Explain how the precision of an instrument is reflected in the number of significant figures that can be written for a measured value. Illustrate your answer by comparing a measurement taken with a vernier calliper having least count 0.1mm and a screw gauge having least count 0.01mm.