What is the main difference between an internal combustion engine and an external combustion engine?

1)the burning of fuel occurs inside the cylinder with the piston in an external combustion engine.

2)an internal combustion engine doesn't have a cylinder and a piston.

3)the burning of fuel occurs inside the cylinder with the piston in an internal combustion engine.

4)an external combustion engine doesn't have a cylinder and a piston

The correct answer is option (3).

Explanation:

Internal combustion engine: An engine which generates motive power by burning the fuel with air inside the engine. Heat produced is used to move piston or to perform other work as they expand.

External combustion engine : An engine where motive power is generated by providing the heat to the fluid present inside the engine from the external source. Here combustion of the fuel is not inside the engine.

Hence,the correct answer is option (3).

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.