Read the text and do the tasksHeat engineA heat engine is a system which converts heat into work by taking heat from the reservoir (hot body) to carry out some work. There is a discharge of some heat to the sink (cold body). In this system, there will also be some waste in the form of heat. There are different types of heat engines, in which a Carnot engine has the maximum efficiency.We know that thermodynamics is the study of the relation between heat and work. The first law of thermodynamics and the second law of thermodynamics help in the operation of the heat engine.The first law is the application of conservation of energy, and the second law sets limits on the possible efficiency of the machine and determines the direction of the flow of energy.Types of Heat EngineThere are mainly two types of heat engines – external combustion engines and internal combustion engines.External combustion engineHere, the fuel gets burnt outside the engine or at a far distance from the engine by which it can produce force and motion. A very good example of an external combustion engine is a steam engine.Water is heated outside or far away from the system by using coal fire, and then the steam produced is given to the top of the metal cylinder through pipes. Heat is given to the engine, and it moves the piston back and forth, and the work is done. The fluid is then cooled, compressed and reused.Internal combustion engineHere, the fuels are burnt inside the chamber. Car engines are a very good example of this type of combustion engine.The heat produced due to combustion is given to the engine, and the work is done. It is also called 4-stroke because it takes 4 strokes for the piston to complete one combustion cycle.So, if we consider both types of heat engines, internal combustion engines are more efficient than external combustion engines. This is because no energy is wasted in an internal combustion engine by transferring heat from the boiler to the cylinder, as in an external combustion engine. Everything happens in one place in internal combustion engines.Working of Heat EngineAs we look earlier, a heat engine contains basically a heat reservoir, an engine and a cold sink. The heat that we produce as internal combustion or external combustion is given to the engine where the movement of the piston takes place. The power generated is given to the machine that is connected to the engine, and hence the work is done. Excess heat is given to the sink, where the temperature will remain the same at both reservoir and sink.Heat engines, like automobile engines, operate in a cyclic manner. They will add energy in the form of heat in one part of the cycle and use this energy to do useful work from another part of the cycle.Examples of Different EnginesSteam EngineA steam engine is a heat engine that gives mechanical work using steam as the working fluid. It uses the force produced by the steam pressure to move the piston forward and backwards inside the chamber. This pushing force is transferred to work. This is a type of external combustion engine in which working fluid is burned out of the chamber, giving the steam to the source using a pipe.Car Engine or Gasoline (Petrol) EngineThis is a type of internal combustion engine where combustion takes place internally. The main purpose of a gasoline car engine is to convert gasoline into motion so that a car can move. The easiest way to produce this motion is to burn the gasoline inside the engine. Here, the air is also used to burn the working fluid.Refrigerator or Heat PumpA normal refrigerator is an example of a heat pump, and in reverse, it is a heat engine. Here, work is used to create a heat differential. Many more cycles can work in reverse to flow heat from the cold side to the hot side. Internal combustion engine parts of these cycles are also not reversible. Heat pump consumes work and is basically used for heating purposes.Beam EngineIt is a type of external combustion engine. In the olden years, the machines that were used were gigantic in size, almost the size of a room. These early devices had a cylinder and a piston attached to a large beam which performed the working of machines.Stirling EnginesNot all external combustion engines are huge and inefficient. Stirling engine consists of two cylinders with a piston powering a single wheel. One cylinder is kept permanently hot, and the other cylinder is kept permanently cold. The engine works as the movement of gas between the cylinders back and forth.Are the statements true or false?1. A heat engine converts work into heat.