Question

In a thermal power plant coal is used for the generation of electricity. How energy changes from one form to another before it is transformed into Electrical energy ?

• A. Heat Energy \(\Rightarrow\) Mechanical Energy \(\Rightarrow\) Electrical Energy
• B. Heat Energy \(\Rightarrow\) Electrical Energy \(\Rightarrow\) Mechanical Energy
• C. Mechanical Energy \(\Rightarrow\) Heat Energy \(\Rightarrow\) Electrical Energy
• D. Electrical Energy \(\Rightarrow\) Heat Energy \(\Rightarrow\) Mechanical Energy

Hint:

Energy conversion in thermal plant: \[ \text{Coal} \rightarrow \text{Heat} \rightarrow \text{Mechanical} \rightarrow \text{Electrical} \]

Answer 1

The Correct Option is A

Concept: A thermal power plant converts the chemical energy stored in coal into electrical energy through multiple stages. The sequence of energy conversion is: \[ \text{Chemical Energy} \rightarrow \text{Heat Energy} \rightarrow \text{Mechanical Energy} \rightarrow \text{Electrical Energy} \] Among the given options, the relevant sequence begins from heat energy.

Step 1: Conversion of coal energy into heat energy. Coal contains: \[ \text{Chemical Energy} \] During combustion in the boiler: \[ \text{Chemical Energy} \rightarrow \text{Heat Energy} \] This heat converts water into high-pressure steam.

Step 2: Conversion of heat energy into mechanical energy. High-pressure steam strikes turbine blades. Thus: \[ \text{Heat Energy} \rightarrow \text{Mechanical Energy} \] The turbine shaft begins rotating.

Step 3: Conversion of mechanical energy into electrical energy. The rotating turbine drives an alternator. According to electromagnetic induction: \[ \text{Mechanical Energy} \rightarrow \text{Electrical Energy} \] Electricity is generated.

Step 4: Writing the overall sequence. Thus: \[ \text{Heat Energy} \rightarrow \text{Mechanical Energy} \rightarrow \text{Electrical Energy} \]

Step 5: Selecting the correct answer. Hence correct option is: \[ \boxed{(1)} \]