1. Blowing air through a capillary immersed in a liquid at...

1. Blowing air through a capillary immersed in a liquid at 298K, the value of $P_{max}$ was measure. - If liquid is water: $P_{max} = 11.82 \times 10^2 (N/m^2)$ - If liquid is aniline: $P_{max} = 701.5 (N/m^2)$ The surface tension of water at 298K is $72.5 \times 10^{-3} (N/m)$. Determine the surface tension of aniline.

Transcript

00:01 Hello students, this question is on drop weight method.

00:05 We have number of drops is equal to 12.

00:09 Weight of drops is given as 0 .971 grams.

00:15 We have diameter equal to 0 .8 centimeter.

00:20 In function f it is equal to 0 .6.

00:24 We have to calculate surface tension.

00:27 Surface tension, tension it is given by formula gamma it is equal to mass m into g, acceleration due to gravity divided by 2 pi r, here r it is inner radius of capillary into function f.

00:49 So here we have average drop mass.

00:57 It is equal to w divided by number of drops that is 12.

01:05 This is equal to 0 .971 grams divided by 12.

01:11 We get m it is equal to 0 .0809 grams.

01:17 From here we can calculate gamma, surface tension it is equal to 0 .0809 grams into 980 centimeter per second square divided by 2 pi into 0 .8 divided by 2, diameter by 2.

01:39 Now this is radius centimeter into 0 .6.

01:45 On calculation we get surface tension it is equal to 52 .57 dyn per centimeter.

01:57 For the second question we are given that a liquid rises in a capillary.

02:02 We have formula for height with which liquid rises in a capillary.

02:25 Here h height it is equal to 2s, s is surface tension, cos theta, theta it is angle of contact divided by r, inner radius of capillary into rho, density of liquid into g, acceleration due to gravity.

02:44 Here we are assuming that angle of contact it is equal to 0 degree...

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