Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Basic principle of marine engine is based on the latent heat energy of fuel is converted into mechanical energy in the case of heat engines.
Reason (R): Combustion takes place inside in the case of steam engine.
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

To easily classify heat engines, remember:
- Internal Combustion Engines (ICE): Diesel and petrol engines (combustion occurs inside the cylinder).
- External Combustion Engines (ECE): Steam engines and turbines (combustion occurs in an external boiler).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Marine engines are heat engines that convert the thermal energy generated by burning fuel into useful mechanical work.
These engines are classified into internal combustion engines (where combustion occurs inside the cylinder) and external combustion engines (where combustion occurs outside the cylinder).

Step 2: Detailed Explanation:
Let us evaluate the Assertion and Reason individually:
Assertion (A):
Heat engines operate by burning fuel to generate heat.
This thermal energy is transferred to a working fluid, where pressure and volume changes convert the heat into mechanical force and motion.
In marine engineering and thermodynamics, this conversion of heat energy into mechanical work is the central principle of propulsion plants.
Therefore, Assertion A is correct in describing this energy conversion.
Reason (R):
A steam engine is an External Combustion Engine (ECE).
In a steam engine, the combustion of fuel occurs outside the engine cylinder in a separate boiler.
The heat from this external combustion boils water to produce high-pressure steam, which is then piped into the engine cylinder to drive the pistons.
Because combustion does not take place inside the engine cylinder, Reason R is false.
Since Assertion A is true but Reason R is false, the correct option is (C).

Step 3: Final Answer:
Assertion (A) is true, but Reason (R) is false because steam engines use external combustion.
Thus, the correct choice is (C).