2. A collection of "free" electrons in one place creates a(n) OA. magnetic field
OB. conductance
OC. electrostatic force
OD. inverse voltage

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

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]