An Otto cycle takes in air at a temperature of 20°C and a pressure of 100 kPa. The high temperature is 1000°C and the compression ratio is 8. The specific heat for air at constant pressure is 1.00 kJ/kg K, and the specific heat for air at constant volume is 0.716 kJ/kg-K. The mass of air in a cylinder is 0.002 kg. If the specific heats stay constant, the clearance volume is most nearly : (A) 90 cm
(B) 120 cm3
(C) 180 cm
(D) 210 cm

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]