11 In thermodynamics heat engines HE are cyclic devices that

(1.1) In thermodynamics, heat engines (HE) are cyclic devices that receive heat from a source at TH, convert some of it to work, and reject the rest to a sink at TL.
True _____ False _____

(1.2) Thermodynamically, the process of baking potatoes with hot air in conventional ovens implies that a particular hot-air oven can be treated as a thermal energy reservoir.
True _____ False _____

(1.3) It is known that the amount of mass or energy entering a control volume is equal to the amount of mass or energy leaving during an unsteady-flow process.
True _____ False _____

(1.4) The boundary work done at constant pressure and at constant volume during expansion of a gas is greater than zero.
True _____ False _____  

(1.5) COP is equivalent to the efficiency of an air-conditioning (AC) or heat pump (HP) unit. A higher value of COP means a higher heating efficiency. True _____ False _____

Solution

1.) - True

because if the work is not produced and the complete energy from the source is rejected to sink then there is no point of calling it as an engine. For example take an automobile engine, if there is no work produced then we would not able to move our vehicle.

2.) - True

From first law of thermodyanmics

dQ= dU + dW for a process

there will be some internal energy for potatoes and the amount of heat you are supplying by the hot conventional air will be utilized to increase the internal energy and also bakes the potates. So it can be considered as a heat reservoir.

3.) - False.

The above statment is true for a steady flow process

4.)- False

work done in constant pressure proceess is PdV

work done in constant volume process is zero.

5.)- True

COP is meant by how well the unit is functioning which resembles efficiency but the only diffenerce between COP and efficiency is COP can never be less than one.