The discharge head of a centrifugal pump will vary directly with the （）.

单项选择题An increase in the heat load to a refrigeration system will cause （）.

A.the suction pressure to decrease
B.the suction temperature to increase
C.increased ice formation on the evaporator coil
D.excessive short cycling of the compressor

单项选择题Which of the following types of hydraulic pumps would be used in a steering system?（）

A.Lobe
B.Screw
C.Radial piston
D.Volute

单项选择题Which of the following statements is true concerning centrifugal pumps?（）

A.They are particularly suited for pumping high viscosity fluids
B.They are started with the discharge valve opened
C.The flow of liquid is developed by imparting energy due to the rotation of an impeller
D.They are always mounted in a horizontal position

单项选择题The temperature of the refrigerant in the evaporator coil depends mostly upon the （）.

A.refrigerant pressure in the evaporator
B.cooling water temperature to the condenser
C.heat load in the refrigerator compartment
D.solenoid valve in the liquid line

单项选择题Refrigerant is circulated through a refrigeration system by the （）.

A.compressor
B.condenser
C.expansion valve
D.evaporator