Questions & Answers

Question

Answers

A) 0.1cm

B) 0.01cm

C) 0.1mm

D) 0.01mm

Answer

Verified

129.9k+ views

$L.C = \dfrac{p}{n}$

Where, $p$ is the pitch and $n$ is the number of divisions on circular scale.

The least count of a screw gauge is defined as the ratio between the pitch and the number of divisions on the circular scale i.e.

$L.C = \dfrac{p}{n}$

Where p= pitch and n= number of divisions on circular scale.

For a standard screw gauge the number of division on the circular scale is always fixed and equals to 100

Therefore, n = 100

Pitch is defined as the linear distance moved by the spindle on giving one complete revolution.

For a standard screw gauge, pitch (p) = 1mm

Therefore,

$L.C = \dfrac{1}{{100}}mm \\$

We can write this as,

$L.C = {10^{ - 2}}mm \\$

On simplifying it, we get

$\Rightarrow L.C = 0.01mm \\ $

Although screw gauge is the more accurate device as compared to vernier callipers, when we need to find the internal diameter of a hollow body then it can’t be measured with the help of screw gauge, in such cases only Vernier callipers are used. This is the limitation of a screw gauge.

Least count of any instrument or device is the least possible measurement that we can take with the help of that particular instrument or device.