Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

(^62) Aptitude Test Problems in Physics
rates. The molar mass of water vapour is
[A, = 18 x 10-3 kg/mol.
Determine the initial Ti and final Tr^
temperature of water and its mass Am.
Hint. Make use of the following tempera-
ture dependence of the saturated water va-
pour pressure:
T, °C 100 120 133 152 180
Psat, X10^6 Pa^1 2 3 5 10
2.23. The lower end of a capillary of radius
r =0.2 mm and length 1=8 cm is immersed
in water whose temperature is constant
and equal to T low = 0 °C. The temperature
of the upper end of the capillary is T up =
100 °C.
Determine the height h to which the wa-
ter in the capillary rises, assuming that
the thermal conductivity of the capillary
is much higher than the thermal conductiv-
ity of water in it. The heat exchange with
the ambient should be neglected.
Hint. Use the following temperature de-
pendence of the surface tension of water:
T, °C^0 20 50 90
a, mN/m 76 73 67 60
2.24. A cylinder with a movable piston
contains air under a pressure pi and a soap
bubble of radius r. The surface tension is
a, and the temperature T is maintained con-
stant.
Determine the pressure p 2 to which the
air should be compressed by slowly pull-