Practice question
Question
A soap film supports 1.8×10−2N over a 35cm slider. What is the surface tension?
Explanation
S = F2l. F = 1.8×10−2N, l = 0.35m. S = 1.8×10−22×0.35 = 0.0257N/m. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.0257 N/m. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.