Practice question
Question
A soap film supports 3.0×10−2N over a 50cm slider. What is the surface tension?
Explanation
S = F2l. F = 3.0×10−2N, l = 0.5m. S = 3.0×10−22×0.5 = 0.03N/m. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.030 N/m. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.