Question

Name the part of vernier calipers which is used to measure depth of a small bottle.
(A). inside small jaw
(B). outside large jaw
(C). Depth rod
(D). Retainer

Answer 1

Hint: The vernier scale is a laboratory instrument which is usually used to measure the diameter of objects. It has several parts which have different functions. It can also be used to measure height or depth. The vernier scale gives one of the most accurate measurements.

Complete answer:
Vernier calipers is an instrument which is used to measure diameter with an accuracy of upto three decimal places. It has various parts.

The jaws are used to hold the object of which the diameter is to be measured.
There are two jaws; the upper jaws are used to measure the inner diameter while the lower jaws are used to measure the outer diameter.
The screw clamp is used to adjust the position of the jaws.
The measurements are made on the main scale and vernier scale.
The least count on the main scale reading is $0.1cm$ while the least count on the vernier scale is $0.002cm$
The total measurement is equal to= $\text{M}\text{.S}\text{.R+V}\text{.S}\text{.R}$
The vernier scale also has a stem which is used for measuring depths of containers; it is called the depth probe.
The depth is measured by lowering the depth probe into the container due to which the jaws move away from each other and along the scales. The reading on the scales is observed as when observed for the diameter and recorded.

Therefore, the vernier caliper has a part called the depth probe which is used to measure heights. Hence, the correct option is (C).

Note:
Least count is the smallest measurement that can be made by an instrument. The error correction is the manufacturing error in the scale of an instrument; it can either be positive or negative. Make sure that there is no forced friction between the main scale and the vernier scale.