Fuels can be broadly classified into how many main types?
Analysis & Theory
Fuels are classified as solid, liquid, and gaseous.
Which of the following is a **solid fuel**?
Analysis & Theory
Coal is a common solid fuel.
Which of the following is a **liquid fuel**?
Analysis & Theory
Kerosene is a liquid fuel used in lamps and stoves.
Which of the following is a **gaseous fuel**?
Analysis & Theory
Butane is a gaseous fuel used in portable stoves and lighters.
The **calorific value** of a fuel is the:
A
Amount of fuel burned per hour
B
Time it takes to ignite
C
Heat energy released per unit mass or volume
D
Temperature of combustion
Analysis & Theory
Calorific value is the amount of heat released during complete combustion of a unit mass or volume of fuel.
Which fuel has the **highest calorific value**?
Analysis & Theory
Hydrogen has the highest calorific value among common fuels (~150 kJ/g).
A **good fuel** should have:
B
Low ignition temperature
Analysis & Theory
Good fuels should release more heat energy (high calorific value) and be clean-burning.
Which of the following is a **renewable fuel**?
Analysis & Theory
Wood is renewable because it can be regrown, unlike fossil fuels.
Which is **not** a property of an ideal fuel?
C
High ignition temperature
Analysis & Theory
A good fuel should ignite easily, so it should have a moderate ignition temperature.
Which of these is **not** a fossil fuel?
Analysis & Theory
Biogas is a renewable fuel produced from organic waste, not a fossil fuel.
What is the **unit** of calorific value in SI?
Analysis & Theory
Calorific value is expressed as Joules per kilogram in SI units.
CNG stands for:
Analysis & Theory
CNG is Compressed Natural Gas, commonly used in vehicles.
Which of these fuels is **used in rockets**?
C
Liquid hydrogen and oxygen
Analysis & Theory
Liquid hydrogen and liquid oxygen are used as rocket propellants.
Which gaseous fuel is **used in households**?
Analysis & Theory
Butane (LPG) is commonly used for domestic cooking.
Which of the following fuels is **least polluting**?
Analysis & Theory
Hydrogen burns cleanly and produces only water vapor.
Which of the following is a **biofuel**?
Analysis & Theory
Ethanol is derived from biomass and is a biofuel.
Ignition temperature is:
A
Minimum temperature at which a fuel ignites
B
Maximum burning temperature
D
Melting point of the fuel
Analysis & Theory
It is the minimum temperature at which a fuel starts to burn.
Which of the following is a **non-renewable fuel**?
Analysis & Theory
Coal is formed over millions of years and cannot be renewed in a short time.
The process of **burning fuel in the presence of oxygen** is called:
Analysis & Theory
Combustion is a chemical process in which a fuel reacts with oxygen to release heat.
Which of the following fuels is used in **nuclear power plants**?
Analysis & Theory
Uranium-235 is a radioactive fuel used in nuclear reactors.