Lactometer

Q. Where can a lactometer be used?

1. To check purity of petrol.
2. To check purity of milk.
3. To differentiate between two liquids having different volumes.
4. To differentiate between two liquids having different densities.

Q. Lactometer works on:

1. Archimedes principle
2. Pascal's principle
3. Fleming's principle
4. Boltzmann principle