Thermal engineering (fuels): identify the incorrect statement about fuels Options compare properties of liquid and solid fuels and desirable fuel characteristics. Choose the single incorrect statement from the list.

Concept/Approach

• Typical gross calorific values: gasoline/petrol ≈ 44–46 MJ/kg; diesel ≈ 42–46 MJ/kg; coal ≈ 24–35 MJ/kg. Thus, liquids are usually higher than common solids.
• Fuels are predominantly hydrocarbons.
• For many practical uses a fuel that lights readily (not excessively high ignition temperature) is desirable; some texts say “moderate to low” ignition temperature.

Why C is incorrect
Statement C reverses the usual trend: solid fuels typically have a lower calorific value than liquid fuels.

Final Answer
Solid fuels have higher calorific value than liquid fuels.