9.7 R = 130 mm
S = 13.6
From Eq. 9.2 for rs <<rm,
Since the sensing line is connected to the column port, this pressure will be negative (below atmospheric) and the pressure should be stated as -17.34 kPa.
9.15 The expansion of the aluminum will decrease the reading while the expansion of the mercury will increase the reading. The temperature change is 15K.
The effect on R of the aluminum scale is:
DRal = -(23´10-6 m/m-K)(15K)(760 mm) = -0.2622 mm
The increased temperature will decrease the density of the mercury. The increase in volume for the mercury is:
DV/V = 1.82´10-4´15 = 2.73´10-3.
Considering the condition at the the hotter temperature to be state 2 and the condition at the initial temperature to be state 1:
The length of the mercury column is inversely proportional to the density (=m/V) and hence
R2Hg/R1Hg = r1/r2 =mV2/(mV1) = V2/V1 = 1.00273
Consequently, the new length of the mercury column is 760(1.00273) = 762.07 and the increase in length is 2.07 mm. The net change in reading is thus 2.07 - 0.2622 = 1.81 mm and the new reading is 761.81 mm.