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.

 

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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 = -(2310-6 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 = 1.8210-415 = 2.7310-3.

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.