Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

H@z@r@h asked in Science & MathematicsPhysics · 1 decade ago

Phenomena on Liquid Surfaces. Help Me Solve This Question?

What work has to be performed to break up 1kg of pure water at 20 Degree Celcius into drops of one micron in diameter at the same temperature? The initial surface of the water is small as compared with the total surface of all the drops and it may be neglected.

1 Answer

Relevance
  • 1 decade ago
    Favorite Answer

    A drop of 1 micrometre diameter has a volume of 4/3 Pi() r^3 = 4/3* PI()* (0.5 * 10 ^ -6)^3

    It has an area of 4* pi()*(0.5 * 10 ^ -6)^2

    And this takes an amount of work = 0.04 * 4 * pi() * (0.5 * 10 ^ -6) ^2

    (Using your value of 0.04 J / m^2 from a previous question)

    So find the number of drops required to make 1Kg of water ( 10 ^ -3 m^3)

    N= 10 ^ -3 / (4/3* PI()* (0.5 * 10 ^ -6)^3) = 1.9 * 10 ^ 15

    Now multiply this by the energy per drop

    = N * 0.04 * 4 * pi() * (0.5 * 10 ^ -6) ^2

    = 240 J

Still have questions? Get your answers by asking now.