Question

Milk purity is measured using:
(a). Hydrometer
(b). Lactometer
(c). Polarimeter
(d). Spectrometer

Answer 1

- Hint- In order to find the measurement instrument first we will understand the principle of gravity of milk and the instrument which will work on this principle will be our answer. We will also study the criterion required to study the purity of mlk.

Complete step-by-step solution -

The principle of gravity of milk which used to find out the content of the water in milk or to test the richness of the milk.
Lactometer is a hydrometer instrument that is used to check for the purity of milk by measuring milk’s density; usually it works on the principle of gravity of milk. Lactometer is consists of a long narrow graduated glass stem which is enlarged in the end into a hollow glass bulb weighted with mercury and lead shots. Numbers registered on the lactometer scale range from 10 or 15 to 40, which record Quevenne’s degrees. The mechanism of the lactometer is based on the Archimedes Principle, when the body floats in a liquid it displaces an amount of liquid equal in weight to the weight of the floating body.
Hence, Milk purity is measured using Lactometer.
So, the correct answer is option B.

Note- Other instruments given in the option are used for the following purpose. A hydrometer is an instrument used for measuring the relative density of liquids based on the concept of buoyancy. A polarimeter is a scientific instrument used to measure the angle of rotation caused by passing polarized light through an optically active substance. A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon.