The apparent weight of a steel sphere immersed in various liquids is measured using a spring balance. The greatest reading is obtained for the liquid

The apparent weight of an object immersed in a liquid is determined by the difference between its actual weight and the upward buoyant force (upthrust) exerted by the liquid [2]. According to Archimedes' Principle, the buoyant force is directly proportional to the density of the liquid and the volume of the displaced fluid [1]. A spring balance measures this apparent weight; therefore, the greatest reading on the balance occurs when the buoyant force is at its minimum [4]. Since the buoyant force decreases as the density of the liquid decreases, the smallest buoyant force—and consequently the highest apparent weight reading—is obtained in the liquid with the smallest density. Depth of submersion does not affect the buoyant force once the sphere is fully submerged, as liquids are nearly incompressible and their density remains constant regardless of depth .

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.13: Let us investigate > p. 76
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Snapshots > p. 77
3. [4] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 9: The Amazing World of Solutes, Solvents, and Solutions > 9.5.3 Effect of pressure on density > p. 148