Name the instrument which can accurately measure the thickness of a paper.
Vernier callipers
Screw gauge
Metre scale
None of these
Screw gauge is used to measure the thickness of a paper as it has the smallest least count.
Name the instrument which can measure accurately the following :
(a) the diameter of a needle,
(b) the thickness of a paper,
(c) the internal diameter of the neck of a water bottle,
(d) the diameter of a pencil.