in previous question, if 15 cm of water and spirit each are further poured into the respective arms of the tube. Difference in the level of mercury in the two arms is (Take, relvative density of mercury = 13.6)

Explanation

On pouring 15.0 cm of water and spirit each into the respective arms of the U tube, the mercury level will rise in the arm containing spirit. Let h ve the difference in the levels of mercury in two arms of U tube and `rho` be the density of mercury.
`:.` The pressure exerted by h cm of mecury column = difference in pressure exerted by water and spirit
`:. h rho g = h_(1)rho_(1) g - h_(2)rho_(2)g` ...(i)
here, `h=? , rho = 13.6 cm^(-3) , h_(1) = 15+10 =25 cm, rho_(1)=1gcm^(-3)`
`h_(2) = 15+12.5=27.5cm, rho_(2) = 0.8g cm^(-3)`
Putting values in (i), we get
`hxx13.6xxg=25xx1 xxg-27.5xx0.8xxg=3g or h=3//3.16=0.22cm`.