The diameters of the two arms of U-tube are 1 mm and 2 mm. The tube is filled partly with water and is kept vertical. If the surface tension of water is 70 dyn. cm^-1, then find the difference in the level of water in the two arms of the U-tube . [Angle of contact=8^@]

The diameters of the two arms of U-tube are 1 mm and 2 mm. The tube is

1.	The diameters of the two arms of U-tube are 1 mm and 2 mm. The tube is filled partly with water and is kept vertical. If the surface tension of water is 70 dyn. cm^-1, then find the difference in the level of water in the two arms of the U-tube . [Angle of contact=8^@]
Answer» Solution :Suppose DUE to capillary action , the water level RISES in one arm of the U-TUBE of `h_1` and in the other arm to `h_2`. `therefore h_1=(2Tcostheta)/( rho G r_1)=(2xx70xxcos8^@)/(1xx980xx0.05)` and `h_2=(2Tcos theta)/(rho g r_2)=(2xx70xxcos8^@)/(1xx980xx0.1)` `therefore` The difference in the level of water in two arms of U tube is `h_1-h_2=(2xx70xxcos8^@)/(1xx980)XX((1)/(0.05)-(1)/(0.1))` `=1.415 cm.`