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Unformatted text preview: capillary diameter D c . This model (Fig. 1) will suggest another method for measuring the surface tension (Ref. I). Determine the height of capillary rise if the liquid is water with surface tension = 0.072 N/m and capillary diameter D c is 10-3 m. Figure 1. Rise of a liquid in a capillary. Problem 1: Correct, Code =4313336481 Solution If we approximate the meniscus as a part of a sphere surface with diameter D c , then the two principal radii of curvature r 1 and r 2 are equal to each other, and are given by r 1 = r 2 = D c The pressure difference across the meniscus is then p atm – p s = p = Where p s is the pressure at the meniscus in the liquid phase. Since the system is in static equilibrium, the pressure p 1 must equal p atm , for these two pressures occur at points that lie in the same horizontal plane in the same fluid. p s + gh = p 1 = p atm Therefore gh = p atm – p s = p = or h = h = = 0.0145 m = 1.45 cm Box the answer(s)!...
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- Fall '13
- Surface tension, Capillary action, 3 m, 0.0145 m, 1.45 cm