The volume of $50\ g$ of a substance is $20\ cm^3$. If the density of water is $1\ gm\ cm^{-3}$, will the substance float or sink?

AcademicPhysicsNCERTClass 9

Given: 
The volume of $50\ g$ of a substance is $20\ cm^3$.

To do:
To check whether the substance will float or sink in water if the density of water is $1\ g cm^{-3}$.

Solution:
To check whether the substance will float or sink, we will have to compare the densities of the subtance and the water.
  • If the density of the substancet is less than that of the water$(1\ g cm^{-3})$, then the substance will float.
  • If the density of the substance is greater than that of the water$(1\ g cm^{-3})$, then the substance will sink.
let us find the density of the substance first and then compare it with that of water:

Density of the substance:

The mass of the substance $=50\ g$

The volume of the substance $=20\ cm^3$

The density of the substance $=\frac{Mass}{Volume}$

Density $=\frac{50}{20}=2.5\ g/cm^3$


Comparison of densities:

On comparing the densities of the substance and water. we know that, the density of water$=1\ g/cm^3$

$2.5\ g/cm^3$ > $1\ g cm^{-3}$

Or, density of the substance > density of the water

Conclusion:
On the basis of the calculation and comparison of densities above we can conclude that the density of the substance is greater than the density of water.
So the substance will sink.
raja
Updated on 10-Oct-2022 13:22:47

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