Second Law of thermodynamics

What is the name of a device that converts thermal energy into work?

• Heating system

• Heat engine

• Refrigerator

• entropy

The efficiency of this heat engine is

• 2.50

• 0.40

• 0.66

• 0.60

A refrigerator is

• A heat engine

• An air cooler

• An electric motor

• A heat engine working in the reverse order

The effeciency of heat engine cannot be 100% because

• all heat energy absorbed is converted into work

• some heat is rejected to the surroundings

• workdone is greater than heat absorbed

• none

The work available in a Carnot cycle is equal to

• The area under the high temperature curve

• the area under the low temperature curve

• the area above the low temperature curve and below the high temperature curve

• none

Which statements are true?

• petrol engine do not need spark plug

• The efficieny of diesel engine is more than petrol engine

• Deisel engine need a spark plug

• The compression ratio of diesel engine is greater than petrol engine

Write down the names of four stroke of petrol engine.

Which engine is in the figure?

• diesel engine

• carnot engine

• petrol engine

• Steam engine

Which statements are true?

• In petrol engine,during combustion ,work is not done.

• In diesel engine,during combustion,work is done

• In internal combustion engine,the compression is adiabatic

• In diesel engine ,air and diesel enter at the same time

In the figure,it is the

• PV diagram of carnot engine

• PV diagram of petrol engine

• PV diagram of diesel engine

• PV diagram of Refrigerator