Question

What is the value of the least count of a commonly available Vernier Callipers?
A. $0.01cm$
B. $0.1cm$
C. $1cm$
D. $1mm$

Answer 1

Hint: The least count of an instrument shows until how much resolution an instrument can provide a reading accurately without any internal errors. Vernier callipers are an instrument which is used to measure the length of any substance. Its range can be smaller than a ruler scale while it cannot measure length which is more than that of micrometer screw gauge.

Complete answer:
There is only up to a certain resolution that any instrument can give correct reading. For example, a ruler can only give accurate reading up to a scale of centimeter or millimeter, but it cannot measure something like a diameter of a strand of a human body’s hair as its dimensions are too low to calculate it from a ruler. A human hair can be calculated in nanometers, while a ruler scale can only measure up to millimeters.

Now, the least count of vernier callipers is minimum resolution, up to which the device can measure a particular quantity accurately. Least count is the division between the smallest reading of the main scale and the total divisions on the vernier scale. The value of least count of the vernier callipers is 0.01cm.

Thus option A is the correct answer.

Note: Here, in the options, they are available in the unit of centimeters and millimeters. But the least count is the division between the quantities which have the same units; hence the least count should be unit less. Here, the unit is how just to bifurcate the numbers from each other, but in reality, least count is unit less.