Abbe's principle of alignment is used in measurements made in .................

The combination of slip gauges to obtain a dimension of $$10.35$$ $$mm$$ will be

A hole is specified as $$\phi 30 \pm 0.04mm$$ with $$\phi \,\,0.01\,\,M.$$ The virtual diameter of the hole (i.e the maximum diameter of the pin that can enter the hole ) is ________________