Heat Engines

What happens to the gas if it is heated inside the engine’s cylinder?

• The gas expands

• The gas contracts

• The gas remains the same

• The gas ignites

What happens to the piston and the gases during compression stroke?

• The piston moves up

• The piston moves down

• The gases expand

• The gases contract

What is the function of the spark plug? What is its effect to the mixture’s temperature?

• It ignites the mixture, increasing the temperature

• It cools the mixture

• It compresses the mixture

• It expands the mixture

In exhaust stroke, what happens to the piston and the mixture of gases?

• The piston moves down, the exhaust valve opens and the burned gas is expelled

• The piston moves up, the exhaust valve closes

• The piston remains still, gases are compressed

• The piston moves down, gases are ignited

What do you think is the effect of this exhaust gas to the environment?

• It will constitute to air pollution

• It will improve air quality

• It has no effect

• It will cause rain

Can we consider heat engine 100% efficient? Why?/Why not?

• No, because some of the gases are exhausted into the environment

• Yes, because it converts all energy

• No, because it loses energy to friction

• Yes, because it is perfectly designed

During the intake stroke, what happens to the piston and the air-fuel mixture?

• The piston moves down, expelling the mixture

• The piston remains still, the mixture is ignited

• The piston moves up, compressing the mixture

• The piston moves down, drawing in the mixture

What is the primary reason a heat engine cannot achieve 100% efficiency?

• Because it is designed for maximum output

• Because some energy is lost as waste heat

• Because it uses mechanical energy

• Because it operates at low temperatures

What are the main components of a refrigeration cycle?

• Refrigerant, Heat Exchanger, Thermostat, Fan

• Compressor, Heat Pump, Condenser, Filter

• Compressor, Condenser, Expansion Valve, Evaporator

• Evaporator, Compressor, Heat Sink, Duct

How does the compressor function in a refrigeration cycle?

• The compressor circulates liquid refrigerant without changing its pressure or temperature.

• The compressor absorbs heat from the environment to maintain low temperatures.

• The compressor cools high-pressure refrigerant gas, lowering its pressure and temperature.

• The compressor compresses low-pressure refrigerant gas, raising its pressure and temperature.