Briefly describe and reason the differences between metals, ceramics, and polymers on the origins/causes of electrical conduction and thermal conduction as a function of temperature and impurity concentration. (b) Why are the differences between metals, ceramics, and polymers in electrical conductivity normally much more significant (up to 10-15 orders of magnitude) than those in thermal conductivity (less than one order of magnitude)

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.