Archimedes' principle is used in MCQ with Answer and Explanation

Explanation:
g = GM/R² = G (ρ 4/3 π R³)/R² ∝ ρ R. If radius half, density same, g becomes half. Weight half = 50 N.

Explanation:
T ∝ 1/√g, g'=4g => T' = T/√4 = T/2.

Explanation:
Speed of sound in air v ∝ √T, where T is absolute temperature in Kelvin. T₀ = 0°C = 273 K, v₀ = 332 m/s. T = 27°C = 300 K. Thus v = v₀√(T/T₀) = 332 × √(300/273) ≈ 332 × √1.099 ≈ 332 × 1.048 ≈ 348 m/s ≈ 350 m/s. Approximate rule: speed increases by 0.6 m/s per °C rise, so 27×0.6≈16.2, 332+16.2≈348.2 m/s. Memory aid: 'v ∝ √T in Kelvin'. Such temperature-dependence problems test application of sound wave properties, common in competitive exams with emphasis on absolute temperature usage.