A student measured the diameter of a wire using a screw gauge with the least count $0.001 \mathrm{~cm}$ and…

A student measured the diameter of a wire using a screw gauge with the least count $0.001 \mathrm{~cm}$ and listed the measurements. The measured value should be recorded as
  1. $5.3200 \mathrm{~cm}$
  2. $5.3 \mathrm{~cm}$
  3. $5.32 \mathrm{~cm}$
  4. $5.320 \mathrm{~cm}$

Solution

The least count (L.C.) of a screw guage is the smallest length which can be measured accurately with it. As least count is $0.001 \mathrm{~cm}=\frac{1}{1000} \mathrm{~cm}$ Hence measured value should be recorded upto 3 decimal places i.e., $5.320 \mathrm{~cm}$

Asked in: JEE Main 2012 (12 May Online)

Practice more Units and Dimensions questions on Aicharya