Question

Consider using the apparatus shown in Fig. 4-1(a), known as the Joule paddle wheel, to determine the specific heat at constant atmospheric pressure. The paddle wheel is driven by a slowly falling weight, and both have a temperature of 14.5 degree C. As a result of the work done by the 0.427 kg mass that falls 1.00 m, the temperature of 1 kg of water rises 1 degree C. Calculate Cp.

Answer 1

Work required to raise the temperature of water,

W = m Cp deltaT

wORK DONEA BY gravity = m g h

m g h = m Cp deltaT

Cp = 0.427 x 9.8 = 4.18 J/kg deg C