Consider a thin circular disk that has been heated up to 100 °c and then left inside a chamber to cool down. the chamber surface is kept at 50 °c and the air inside is maintained at 20 °c. assume that the disk is held at the center of the chamber and the heat conduction is neglectable. what is the total rate of heat transfer from the disk? the disk diameter is 500 mm and the surface emissivity is ε = 0.5. note: air properties: υ = 20.92×10-6 m2 /s, k = 30×10-3 w/mk, pr = 0.7, α = 29.9×10-6 m2 /s and

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.

could you add the photo?

explanation: