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Correct Answer: Option (B) — 10 cm
Concept & Option Breakdown
Standard Reference VerifiedLet side length of the cube be $l\text{ cm}$. When the $0.2\text{ kg} = 200\text{ g}$ mass is removed, the extra submerged volume of height $2\text{ cm}$ emerges from water. The weight of water displaced by this emerging volume equals the removed mass: $\text{Mass removed} = \text{Volume displaced} \times \rho_{\text{water}}$ $200\text{ g} = (l \times l \times 2\text{ cm}) \times 1\text{ g/cm}^3$ $200 = 2 l^2 \implies l^2 = 100 \implies l = 10\text{ cm}$.
Removed mass = mass of water in the emerged slab: $200\text{ g} = l^2 \times 2 \times 1 \implies l = 10\text{ cm}$.
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