Question

30 cm scale which of the following cannot measure using this
a -1.0 cm
b -2.4cm
c -1.0mm
d - 0.2mm​

Answer 1

d - 0.2mm
because this quantity cannot be measured with the help of normal scale.
to measure the smaller quantities like 0.2mm,0.4 mm etc. we use A vernier scale on caliper may have a least count of 0.1 mm.