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    Question

    Two parallel wires of length 10 cm each are separated by

    a distance of 0.5 cm in a liquid. If the distance between them is increased by 2 mm, how much work is done? (Surface tension = 72 dyne/cm)
    A 144 ergs Correct Answer Incorrect Answer
    B 72 ergs Correct Answer Incorrect Answer
    C 288 ergs Correct Answer Incorrect Answer
    D 216 ergs Correct Answer Incorrect Answer

    Solution

    W=T×ΔA ΔA=2×length×Δd Substituting values: W=72×2×10×0.2=288 ergs

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