Question

The principle which a lactometer work is
(a)Viscosity
(b)Density
(c)Surface tension
(d)Presence of protein

Answer 1

It is an instrument that is basically used for the milk industries and dairy farm. It is used for the purity of milk. The milk is pure when the specific gravity of a sample of milk is within the approved ranges. If it is not in the approved range, then there is some adulteration. The specific gravity of milk is 1.028-1.032 kg/liter.

Complete answer:
Lactometer is generally a hydrometer which functions according to the Archimedes Principle. Furthermore, Archimedes Principle expresses "any object partially or completely immersed in a fluid is buoyed or lifted up by a force, which is equivalent to the weight of the fluid displaced by the object". In this manner bring down the density of milk, more the lactometer sinks. The buoyant force is the force that acts upwards to decrease the real weight of the object.

Additional Information: There are various types of lactometer like mercury coated lactometer which is highly acknowledged for its precision design and efficiency. And the other type of lactometer is the steel ball lactometer which is known for its accuracy and longer working life. A lactometer also measures the cream content of milk. When the cream is more than it, lowers the lactometer floats in the milk.

So, the correct answer is ‘Density’.

Note: Lactometer consists of a long thin graduated glass stem that is augmented at long last into an empty glass bulb weighted with mercury and lead shots. Numbers listed on the lactometer scale that record Quevenne's degrees range from 10 or 15 to 40. Lactometers are very much used for industrial purposes where the milk which is manufactured is tested first and then is sent to make various products.