(a) The figure shows a drop of liquid on glass. Is the contact angle greater than 90 or less than 90?
© Department of Physics, University of Guelph
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1. A soap bubble is in a chamber pressurized to 1.20 atmospheres of air (absolute pressure). The bubble is 1.00 × 10-2 mm in diameter. What is the absolute pressure inside the bubble? (use γ = 7.30 × 10-2 N/m)
2. The soap solution (s.g. = 1.00) used to make the bubble in question #1 is standing in an open vertical tank.
(a) How far below the surface must a
bubble
be to experience the same external pressure as in question 1?
(b) If the bubble is 1.00 × 102
mm in diameter, what is the absolute pressure inside the bubble?
3. Two soap bubbles are floating around in air. One is twice the volume of the other. The excess pressure inside the larger bubble is approximately That inside the smaller bubble.
4.
(a) The figure shows a drop of liquid on
glass. Is the contact angle greater than 90 or less than 90?
(b) If a glass tube were dipped in a
beaker
of the liquid, would the liquid rise up the tube (capillary rise) or go
down in the tube (capillary fall)? Give your reasoning. (Be brief.)