A vertical U-tube of uniform cross-section contains mercury in both sides of its arms as shown below.Glycerin column of 10 cm is introduced into one of its arms. Oil of density 0.8 g/cc is poured into the other arm until the upper surface of the oil and glycerin are at thesame horizontal level.ρHg=13.6g/cc,ρglycerine=1.3g/ccThe length of oil column is