In an interference microscope, a groove produces a band distortion of $$4$$ band spacing. If the wave length of the monochromatic light source is $$0.5microns,$$ the groove depth is ......................$$mm$$

In mass manufacturing, two holes in a plate type of component are ideally located with the help of

The fit on a hole-shaft pair system is specified as $$H7$$-$$s6$$. The type of fit is

The diameter of the best wire to measure the effective diameter of a metric screw threads of $$0.5$$ $$mm$$ pitch is ......... $$mm$$