A thermistor is connected in series with a series resistor of 1,000 Ohms. The supply voltage is 20 V DC and the material constant of the thermistor is 4,000 K. A
voltmeter of internal resistance 100 Ohms is connected across the series resistor.
At room temperature of 25°C, the voitmeter gives a reading of 2 V. The thermistor
is used to measure the temperature of a material and the reading of the voitmeter
is 4 V. What is the temperature of the material?
(10 marks]

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.