Question

Compared to petrol operated-engine, an ethanol operated-engine
a) Produces 50% more power
b) Produces 20% more power
c) Produces comparable amount of power
d) Produces 20% less power​

Answer 1

OPTION (b) IS CORRECT.

b) PRODUCES 20% MORE POWER

Explanation:

• When petrol is burnt more energy is produced than ethanol.
• 1L of ethanol is burnt to give 23.5 million J of energy whereas ethanol gives 33.5 million J of energy.
• Petrol operated engine produces more 20% more energy.
• But ethanol is more efficient as it produces less carbon dioxide than petrol.
• Ethanol has more octane rating, so the engine filled with ethanol can handle more compression.
• Therefore, option (b) is correct.