A long solenoid has a radius of 3cm, 5,000 turns/m, and carries current I = 0.25 A. The region

0 < ? < a within the solenoid has ?r = 5, while ?r = 1 for a < ? < 3 cm.

a) Find a so that a total flux of 10 ?Wb is present.
b) Find a so that the flux is equally-divided between the regions 0 < ? < a and a < ? < 3cm.

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.