Practice question
Question
A manometer with mercury (ρ\=13.6×103kg/m3) shows a height difference of 20cm. What is the pressure difference? (Take g\=9.8m/s2)
Explanation
ΔP = ρgh. ρ = 13.6×103kg/m3, g = 9.8m/s2, h = 0.2m. ΔP = 13.6×103×9.8×0.2 = 26656Pa. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.67 × 10⁴ Pa. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.