Archimedes' principle: upthrust equals weight of displaced fluid

Steps:

• Volume of block is L × 2L × 4L = 8L³, fully submerged both times.
• Initial upthrust U = ρ g × 8L³, where ρ is water density.
• Rotation changes orientation but not submerged volume.
• New upthrust = ρ g × 8L³ = U.

Why B is correct:

• Upthrust depends solely on displaced volume per Archimedes' principle, unchanged by rotation.

Why the others are wrong:

• A: Confuses upthrust with base area ratio (smallest to largest is 1/4).
• C: Assumes upthrust doubles with height change, but volume is fixed.
• D: Assumes upthrust quadruples inversely with base area, ignoring volume.

Final answer: B