Question

Calculate the diameter of a capillary tube in which mercury is depressed by 2.219 mm. Given T for mercury is 0.54 N m-1, angle of contact is 140° and density of mercury is 13600 kg m-3
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Answer 1

Answer:

Height of mercury depressed in capillary

h =−2Tcosθρgr ⇒ r= 2T cosθρgh r=−2×540×cos 140013.6×980×1.219 r= 2×540×0.7613.6×980×1.219 = 827.3216246.83 [ρ= 13.6 g/cm3 r= 0.05 cm g= 980 cm/s2] Diameter = 2×0.05 = 0.10 cm