HEAT ENGINE AND THERMAL EFFICIENCY

1. Which is the correct sequence of the four-stroke cycle?

• A. Intake, Compression, Power and Exhaust Stroke

• B. Power, Intake, Exhaust, and Compression Stroke

• C. Compression, Power, Intake, and Exhaust Stroke

• D. Power, Compression, Intake and Exhaust Stroke

2.What is the function of heat engine?

• A. It converts chemical energy to mechanical energy.

• B. It converts thermal energy to mechanical energy.

• C. It converts mechanical energy to chemical energy.

• D. It converts thermal energy to chemical energy.

3.Why is heat engine not 100% efficient?

• A. Because all mixture of gases is converted into work.

• B. Because engine needs to be cooled down.

• C. All the gases are used up by the engine.

• D. Some of the gases is taken up in the piston.

Answer explanation

The engine of course are 30% efficient only .That means that for every 100 joules of thermal energy produced by the combustion of gasoline only 30 joules are used to operate the vehicle.

4. What causes thermal energy?

• A. exhaust of different vehicles.

• B. exhaust from different industrial engines.

• C. degradation of water.

• D. All of them

5. What is the function of the spark plug?

• A. The spark plug ignites the mixture making it temperature high.

• B. The spark plug pushes the piston down

• C. The spark plug pushes the piston up.

• D. The spark plug pushes the gases out of the cylinder.