3. 2073 Supp. Q.No. [tex]$2 b$[/tex]

केही वस्तुहरूको घनत्व तालिकामा दिइएको छ। उक्त तालिका अध्ययन गरी निम्न प्रश्नहरूको उत्तर दिनुहोस्।
(Density of some substances is given in a table. Study the table and answer the following questions:)

\begin{tabular}{|c|c|}
\hline वस्तु (Substances) & घनत्व (Density) \\
\hline [tex]$X$[/tex] & [tex]$11 \, \text{gm/cm}^3$[/tex] \\
\hline [tex]$Y$[/tex] & [tex]$8 \, \text{gm/cm}^3$[/tex] \\
\hline [tex]$Z$[/tex] & [tex]$0.9 \, \text{gm/cm}^3$[/tex] \\
\hline
\end{tabular}

i. समान पिण्ड भएका तीनैओटा मध्ये सबभन्दा कम आयतन कुन वस्तुको होला? (Which substance will have the least volume if equal masses of all are taken?)

ii. समान आयतन भएका तीनैओटा मध्ये सबभन्दा कम पिण्ड कुन वस्तुको होला? (Which substance will have the least mass if equal volume of all are taken?)

iii. कुन वस्तु पानीमा उत्रिएला? (Which one will float on water?)



Answer :

Certainly, let’s proceed step-by-step to solve these questions based on the given table of densities.

### Given Table of Densities:
[tex]\[ \begin{array}{|c|c|} \hline \text{Substances} & \text{Density (gm/cm}^3\text{)} \\ \hline X & 11 \\ \hline Y & 8 \\ \hline Z & 0.9 \\ \hline \end{array} \][/tex]

### i. समान पिण्ड भएका तीनैओटा मध्ये सबभन्दा कम आयतन कुन वस्तुको होला ? (Which substance will have least volume if equal masses of all are taken?)

For equal masses, the volume [tex]\( V \)[/tex] is inversely proportional to the density ([tex]\( \rho \)[/tex]). This means that a substance with a higher density will occupy less volume.

- Density of [tex]\( X \)[/tex]: [tex]\( 11 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Y \)[/tex]: [tex]\( 8 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Z \)[/tex]: [tex]\( 0.9 \, gm/cm^3 \)[/tex]

Among [tex]\( X, Y, \)[/tex] and [tex]\( Z \)[/tex], substance [tex]\( X \)[/tex] has the highest density ([tex]\( 11 \, gm/cm^3 \)[/tex]). Hence, substance [tex]\( X \)[/tex] will have the least volume when masses are equal.

Answer: The substance with the least volume for equal masses is [tex]\( \mathbf{X} \)[/tex].

### ii. समान आयतन भएका तीनैओटा मध्ये सबभन्दा कम पिण्ड कुन वस्तुको होला ? (Which substance will have the least mass if equal volume of all are taken?)

For equal volumes, the mass [tex]\( m \)[/tex] is directly proportional to the density ([tex]\( \rho \)[/tex]). This means that a substance with a lower density will have less mass.

- Density of [tex]\( X \)[/tex]: [tex]\( 11 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Y \)[/tex]: [tex]\( 8 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Z \)[/tex]: [tex]\( 0.9 \, gm/cm^3 \)[/tex]

Among [tex]\( X, Y, \)[/tex] and [tex]\( Z \)[/tex], substance [tex]\( Z \)[/tex] has the lowest density ([tex]\( 0.9 \, gm/cm^3 \)[/tex]). Hence, substance [tex]\( Z \)[/tex] will have the least mass when volumes are equal.

Answer: The substance with the least mass for equal volumes is [tex]\( \mathbf{Z} \)[/tex].

### iii. कुन वस्तु पानीमा उत्रिएला ? (Which one will float on water?)

A substance will float on water if its density is less than that of water. The density of water is [tex]\( 1 \, gm/cm^3 \)[/tex].

- Density of [tex]\( X \)[/tex]: [tex]\( 11 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Y \)[/tex]: [tex]\( 8 \, gm/cm^3 \)[/tex]
- Density of [tex]\( Z \)[/tex]: [tex]\( 0.9 \, gm/cm^3 \)[/tex]

Among these substances, only [tex]\( Z \)[/tex] has a density less than water ([tex]\( 0.9 \, gm/cm^3 < 1 \, gm/cm^3 \)[/tex]). Hence, substance [tex]\( Z \)[/tex] will float on water.

Answer: The substance that will float on water is [tex]\( \mathbf{Z} \)[/tex].

### Summary of Answers:
1. Least volume for equal masses: [tex]\( \mathbf{X} \)[/tex]
2. Least mass for equal volumes: [tex]\( \mathbf{Z} \)[/tex]
3. Will float on water: [tex]\( \mathbf{Z} \)[/tex]