Question

what is upthrust?(b)write applications of (i)Lactometer,(ii)Hydrometer

Answer 1

a) ANS: - The upward force experienced by a body when it is partly or wholly immersed in a fluid is called buoyant force or upthrust. (it is also defined as the weight of the fluid displaced by the immersed part of the body.)

b) ANS: -
Uses of lactometer:
• To find the purity of milk
• To find the density of liquid
• To check adulteration of water


A hydrometer is used to find relative density of fluids.

Answer 2

When an object is immersed in a fluid , it experiences an upward force known as buoyant force / upthrust.

Upthrust = volume x density x acceleration due to gravity

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i) Lactometer is used to check the purity of milk.

ii) Hydrometer is used to check the relative density of fluids


Both of the devices works on the Archimedes principle