1) What is the least count of a screw gauge?
Generally, 0.001 cm or 0.01 mm is the least count of a screw gauge, but for more precise results, micrometre can also be used.
2) What is Vernier’s calliper?
A French mathematician, Pierre Vernier, introduced a device used for measuring very precise linear measurements; this device was named Vernier callipers. It was introduced in 1631 and is extensively used for manufacturing quality control measurements in scientific laboratories.
3) What is the least count of Vernier calliper?
The least division on the main scale divided by the number of divisions on the Vernier scale is the least count of a Vernier calliper.
Therefore, the least count of Vernier calliper is = 0.1 mm, that is, (1mm/10 divisions)
4) What are the uses of a Vernier calliper?
Following are some uses of Vernier callipers:
(i) Vernier callipers are used to measure the length of a rod or any object
(ii) Vernier callipers help to measure the diameter of a sphere
(iii) Vernier callipers are also used to measure the exterior and interior diameter of a hollow cylinder and the depth of a small beaker.
5) What is meant by zero error of vernier callipers?
The vernier callipers are said to have zero error when the zero mark of the vernier scale does not overlap with the zero mark of the main scale due to mechanical errors.
By measuring the distance between the zero mark of the vernier scale and the zero mark of the main scale, zero error can be determined.
There are two types of zero error:
(i) Positive zero error
(ii) Negative zero error
6) What is the Vernier constant?
The difference between the value of one vernier scale division and one main scale division on the vernier callipers is known as the Vernier constant.
7) What do you mean by systematic error?
Either positive or negative, the errors which arise in one direction are known as systematic errors. Due to the improper setting of instruments, personal errors arise. Therefore, it also comes under the category of systematic error.
8) All physical quantities have dimensions; is it true or false?
The above statement is false because all physical quantities do not have dimensions. Some examples of dimensionless quantities are angle, relative density and strain.
9) Without being accurate, an instrument cannot be precise; is it true or false?
The above statement is false because an instrument cannot be accurate without being precise, but the instrument can be precise without being accurate.
10) Using a scale, can you measure the diameter of a thread?
Yes, the diameter of the thread can be measured by winding the thread on a metre scale in such a way that its turns are close together. And then, the number of turns made by the thread is counted and also the thickness of the thread coil is measured. Now, the diameter is then calculated by dividing the total thickness of the wound by the number of turns.
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