Q2: The temperature of a gas steam is to be measured by a thermocouple. Determine the time it take: p =8500 kg/m _and C-320 J/kg to register 99% of the initial AT . For junction k=35 W/m.°C Ans : 38.5 sec Gas Junction D. h. T. 11111

it is desired to understand the time - temperature behavior of a hot copper sphere. the sphere has a diameter D and Is buried a depth Z below the surface of the dry sand in a very large,very deep sand pit far from the edges of the pit. The initial temperature of the sphere is Ti, and the temperature at the surface of the sand is maintained at "T infinity". the difference between the temperature of the sphere and the surface, T - Tinfinity at any time is a function of the initial Temperature difference, Ti - Tinfinity ; the thermal conductivity of the sand, ks ; the thermal conductivity of the copper kc ; the sphere diameter D ; the depth at which it is buried Z; the elapsed time t, and the density times the specific heat Pcp of the copper. What is the best set of repeating variables for this problem? Find the appropiate functional relationship between these parameters in dimensionless form.

Recall that a there fore thermodynamie detinihon Constant pressure, AH = 9. We can from the caleulate AS for any process S= arev こ ナ Use this informmaton to deprive dAS an expressiom for but temperature - Invariant heat capacuty change s Cp. Integrate this equathon Such that Calculate the AS at any temp T given a known value AS, at To for a process Involving a non-zero you Can

Please explain and answer