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Q13
(NDA-II/2022)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic mechanics concepts
An object is made of two eal parts by volume?
Result
Your answer:
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Correct:
A
Explanation
Density is defined as mass per unit volume [1]. For a composite object made of two equal parts by volume, the total volume (V) is the sum of the individual volumes (V1 + V2), where V1 = V2 = V/2. According to the rule of mixtures, the total mass of the composite is the sum of the masses of its constituents. Since mass equals density multiplied by volume, the total mass is (ρ1 * V/2) + (ρ2 * V/2). The average density of the composite object is calculated by dividing the total mass by the total volume: (ρ1 * V/2 + ρ2 * V/2) / V. This simplifies to (ρ1 + ρ2) / 2, which is the arithmetic mean of the densities of the two parts. This formula applies specifically when the volume fractions of the components are equal.
Sources
- [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 9: The Amazing World of Solutes, Solvents, and Solutions > How do scientists define density? > p. 140
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