A soap film on a wire supports 1.2×10−2N over a 25cm slider. What is the surface tension?
S = F2l, F = 1.2×10−2N, l = 0.25m. S = 1.2×10−22×0.25 = 0.024N/m. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.024 N/m. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.