Question

The fig. below shows a thin liquid supporting a small weight 4.5 × 10^–2 N. What is the weight supported by a film of same liquid at the same temperature in fig. (b) & (c). Explain your answer. 

Answer 1

The weight supported by (b) and (c) are same as that in (a) and is equal to 4.5 × 10^–2 N. The weight supported = 2 σ l, where σ is surface tension and l is the length which is same in all the three cases, hence weight supported is same.