Practice question
Question
A bubble of radius 4.0mm is blown at 60cm depth in a soap solution (ρ\=1.2×103kg/m3, S\=0.025N/m). What is the total pressure inside? (Take Pa\=1.01×105Pa, g\=10m/s2)
Explanation
Pi = Pa+ρgh+2Sr. Pa = 1.01×105Pa, ρgh = 1.2×103×10×0.6 = 7200Pa. 2Sr = 2×0.0254.0×10−3 = 12.5Pa. Pi = 1.01×105+7200+12.5 = 1.082125×105Pa. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.08 × 10⁵ Pa. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.