Solid state physics is the branch specifically concerned with the structure and properties of solid materials.

Pressure at 200 m is ρgh = 1000×10×200 = 2×10^6 Pa; K = ΔP/(ΔV/V) = 2×10^6 / 1×10^-3 = 2×10^9 Pa, matching option B (OCR-superscript garbling).

One hectare equals approximately 2.47 acres; the OCR shows the first option marked on the page.

Angular momentum has units kg·m^2·s^-1, so option D (kg m2 s-1) is correct.

Extension is inversely proportional to area; doubling area halves the extension: 0.1 mm × (4/8) = 0.05 mm.

The increased buoyant force when pushed down provides a restoring force so the balloon rises back to its equilibrium position.

Surface tension depends on the liquid's nature, temperature, and impurities, but is essentially independent of the external atmospheric pressure.

Angular velocity is measured in radians per second (rad s^-1), so option D is correct.

SI base quantities (fundamental quantities) are defined and measured directly, making them the ones measured most accurately.

Drain time scales with √height for Torricelli flow; integrating shows time to drain from H to 0 ∝ √H, so time from H/2 to 0 ≈ 10×(1-1/√2) ≈ 3 minutes.