Characteristics of a Good Fuel - UNSOLVED PRACTICE SET
Chapter: Sources of Energy | Topic: Good Fuel Characteristics
CHARACTERISTICS OF A GOOD FUEL - UNSOLVED PRACTICE SET
Topic: Good Fuel Characteristics
Multiple Choice Questions
Q1. Type your question here...
- Ignition temperature
- Calorific value
- Combustion rate
- Energy density ratio
Q2. The SI unit of calorific value of a fuel is:
- Joule
- Watt
- Joule per kilogram (J/kg)
- Calorie per second
Q3. A good fuel should have:
- Low calorific value and high ash content
- High calorific value and low ash/residue content
- Low ignition temperature causing spontaneous combustion at room temperature
- High cost and limited availability
Q4. Which of the following is generally considered a CLEANER fuel in terms of pollution?
- Coal
- Wood
- CNG (Compressed Natural Gas)
- Cow dung cakes
Q5. Ignition temperature of a fuel refers to:
- Ignition temperature of a fuel refers to:
- The minimum temperature at which a fuel catches fire and continues to burn
- The maximum safe storage temperature
- The temperature at which a fuel stops burning
Q6. Hydrogen has one of the highest calorific values among common fuels. A major challenge in using hydrogen as a vehicle fuel is:
- It produces too much ash
- It is difficult and costly to store and transport safely
- It has a very low calorific value
- It cannot be ignited at all
Short Answer Questions
Q7. List four characteristics of an ideal fuel. For each, briefly explain why it matters.
Q8. Define calorific value. If Fuel A has a calorific value of 50,000 kJ/kg and Fuel B has 30,000 kJ/kg, what does this comparison tell us about the two fuels?
Q9. Why is LPG (Liquefied Petroleum Gas) preferred over wood or coal as a cooking fuel in most Indian urban households today? Give two reasons.
Q10. What does 'ignition temperature' mean? Why is it important for a fuel to NOT have too low an ignition temperature?
Q11. Burning of fuels like coal and diesel produces harmful gases. Name two such gases and state one environmental effect of each.
Q12. Why is it important for a fuel to be easily transportable and storable? Compare the ease of transport of CNG vs firewood for a household in a remote Himalayan village.
SECTION NAME
Q13. Discuss the characteristics of an ideal fuel in detail. Your answer must cover:
(a) high calorific value and why it matters,
(b) appropriate ignition temperature (not too high, not too low) and the safety implications,
(c) low production of smoke/ash and harmful gases,
(d) easy availability, storage, and transportability, and
(e) for each characteristic, name one common fuel (from wood, coal, kerosene, LPG, CNG, hydrogen) that performs well and one that performs poorly on that characteristic.
Q14. A family in rural Bihar traditionally cooks using wood and cow dung cakes, but is now considering switching to LPG under a government scheme (like Ujjwala Yojana).
(a) Compare wood/dung cakes and LPG on at least four characteristics of a good fuel (calorific value, smoke production, ease of storage, cost).
(b) What health benefits would the family experience by switching to LPG?
(c) What environmental benefits would result, both for the household and more broadly?
(d) What practical challenges might the family face in switching completely to LPG (think about cost, refill availability, habit)?
Q15. No single fuel is 'perfect' — every fuel involves trade-offs. Analyse the following fuels with respect to the characteristics of an ideal fuel: petrol (used in cars), CNG (used in auto-rickshaws in Delhi), and hydrogen (an emerging fuel). For each fuel:
(a) state its approximate calorific value (relative comparison is fine),
(b) discuss its environmental impact,
(c) discuss practical challenges in storage/transport, and
(d) conclude by explaining why the 'best' fuel choice often depends on the specific application (e.g., a rocket vs a two-wheeler vs a power plant).
Numerical / Application-Based Problems
Q16. The calorific value of LPG is approximately 45,000 kJ/kg, and that of wood is approximately 17,000 kJ/kg.
(a) How much heat energy is released by burning 2 kg of LPG?
(b) How many kilograms of wood would need to be burnt to release the same amount of heat energy as 2 kg of LPG?
(c) Based on this calculation, explain (in 1-2 sentences) one practical advantage of LPG for cooking in terms of the quantity of fuel a household needs to store.
Q17. A school canteen uses a gas stove (LPG, calorific value 45,000 kJ/kg) to heat water for tea every morning. They need 9,000 kJ of heat energy daily for this purpose.
(a) Calculate the mass of LPG required per day (assuming 100% efficiency, which is unrealistic but useful for this estimate).
(b) If the actual efficiency of the stove is only 60% (some heat is lost to surroundings), calculate the actual mass of LPG needed per day.
(c) Over a 200-day school year, calculate the total LPG consumption in kg.
Q18. A comparison table for three fuels is given:
Fuel A: Calorific value = 30,000 kJ/kg, produces high smoke, ignition temp = 400°C
Fuel B: Calorific value = 50,000 kJ/kg, produces low smoke, ignition temp = 580°C\n Fuel C: Calorific value = 20,000 kJ/kg, produces moderate smoke, ignition temp = 250°C
(a) Which fuel would deliver the most heat energy per kg burnt?
(b) Which fuel would be considered 'safest' to store at room temperature (least likely to catch fire accidentally) based on ignition temperature?
(c) Which fuel is likely the LEAST environmentally friendly based on smoke production?
(d) If you had to choose a fuel for a household kitchen, which one (A, B, or C) would you recommend and why, considering ALL three properties together?