Question

Which of the following statements are true for relative density?

• A. It has no units
  
• B. Objects with relative density lower than 1 will float on water
  
• C. It is the ratio of mass of a certain volume of a substance to the mass of the same volume of water at $4^{\circ }C$.
  
• D. It is also known as specific gravity
  

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A It has no units
B Objects with relative density lower than 1 will float on water
C It is the ratio of mass of a certain volume of a substance to the mass of the same volume of water at $4^{\circ }C$.
D It is also known as specific gravity

Explanation: relative density is defined as the ratio of density of any substance to the density of water at $4^{\circ }C$. since water is densest at $4^{\circ }C$ i.e. 1 and is regarded as a standard to calculate the relative density of any substance. Since it is the ratio of two similar quantities it has no units. As density is mass per unit volume, relative density is also defined as the ratio of mass of a certain volume of a substance to the mass of the same volume of water at $4^{\circ }C$. it is also known as the specific gravity of a substance because specific gravity is also the ratio of the density of a substance with the density of water.