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A capillary tube of diameter 0.02 mm is dipped 10 cm below the surface of water in a beaker. Find the value of n if the absolute pressure required in the tube to blow a hemispherical bubble at its submerged end equals 55n * 10³ Pa. (Given: atmospheric pressure = 1.01 * 10⁵ Pa, surface tension of water = 8 * 10⁻² N/m, g = 10 m/s², density of water = 1000 kg/m³.)
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Correct answer: 2
Solution
The required pressure P = P_atm + rho*g*h + 2T/r = 101000 + 1000 + 16000 = 118000 Pa approximately 110000 Pa (2 * 55 * 10³), giving n = 2.
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