ETD Quiz (Module 2)

According to Clausis statement of second law of thermodynamics

• heat can’t be transferred from low temperature source to high temperature source

• heat can be transferred for low temperature to high temperature source by using refrigeration cycle.

• heat can be transferred from low temperature to high temperature source if COP of process is more than unity

• heat can’t be transferred from low temperature to high temperature source without the aid of external energy

Carnot cycle has maximum efficiency for

• petrol engine

• reversible engine

• irreversible engine

• new engine

COP of a refrigerator is always

• Equal to 1

• Less than 1

• Greater than 1

• Equal to 0

Relation between cop of heat pump and refrigerator

• COP(Heat Pump)=COP(Refrigerator)+1

• COP(Refrigerator)=COP(Heat Pump)+1

• COP(Heat Pump)=COP(Refrigerator)

• COP(Heat Pump)+COP(Refrigerator)=1

The heat taken from the sink is based on

• First law of thermodynamics

• Second law of thermodynamics

• Third law of thermodynamics

• Zeroth law of thermodynamics

For a heat engine operating between two temperatures (T2 > T1), what is the maximum efficiency attainable?

• 1 - (T1/T2)

• 1 - (T2/T1)

• T1 - T2

• 1 - (T12/T2)

Why can't a heat engine be 100% efficient?

• No work can be done

• Heat must be constantly created

• Entropy is lost

• Thermal energy decreases

The efficiency of this heat engine is

• 0.2

• 0.6

• 0.4

• 0.5

Carnot cycle efficiency is

• 1-(Qr/Qs)

• 1-(Qs/Qr)

• 100%

• None

The food compartment of a refrigerator is maintained at 4°C by removing heat from it at a rate of 360 kJ/min. If the required power input to the refrigerator is 2kW, determine the coefficient of performance of the refrigerator.

• 4

• 3

• 2

• 1