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Work done in increasing the separation of two parallel wires holding a liquid film

The same question, asked 2 times: 4 May 2023 S2*, 9 May 2024 S2. Every wording below, oldest first.

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  1. Question 1

    4 May 2023 S2

    17
    A water film is formed between two parallel wires of 10 cm length. The distance of 0.5 cm between the wires is increased by 1 mm. The work done in the process is (surface tension of water =72= 72 N/m)

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  2. Question 2

    9 May 2024 S2

    34
    A film of soap solution is formed between two straight parallel wires of length 10 cm each separated by 0.5 cm. If their separation is increased by 1 mm while still maintaining their parallelism. How much work will have to be done? (surface tension of solution =65×10−2= 65 \times 10^{-2} N/m)

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