In an open U-tube containing mercury, kerosene of specific gravity 0.8 is poured into one of its limbs so that the length of column of kerosene is about 40 cm. The level of mercury column in that limb is lowered approximately by how much?
1
2.4 cm
2
1.2 cm
3
3.6 cm
4
0.6 cm
5
1.6 cm