1.
A chemical process in which a volatile substance reacts rapidly with oxygen and gives off heat.
Correct Answer
A. Combustion
Explanation
Combustion is the correct answer because it refers to a chemical process where a volatile substance reacts rapidly with oxygen and releases heat. During combustion, the substance undergoes oxidation and burning, resulting in the transformation of the original substance into different products.
2.
For an airplane propulsion system, the fuel usually used is.
Correct Answer
B. Liquid
Explanation
The correct answer is liquid because most airplane propulsion systems use liquid fuel. Liquid fuels, such as jet fuel or kerosene, are preferred for aircraft engines due to their high energy density and ease of handling. Liquid fuels can be easily stored and transported, making them suitable for long flights. Additionally, liquid fuels provide a more efficient combustion process, resulting in better performance and reduced emissions.
3.
During the combustion process, new chemical substances are created from the fuel and the oxidizer, these substances are called.
Correct Answer
C. Exhaust gas
Explanation
During the combustion process, fuel reacts with an oxidizer to produce new chemical substances. These substances are released as exhaust gas. Exhaust gas is a byproduct of combustion and typically contains various gases such as carbon dioxide, carbon monoxide, nitrogen oxides, and water vapor. It is generated in engines, power plants, and other combustion processes.
4.
For an airplane propulsion system, the oxidizer usually used is.
Correct Answer
A. Gas
Explanation
In an airplane propulsion system, the oxidizer is usually in the form of a gas. This is because gases are easier to handle and transport compared to liquids or solids. They can be stored in tanks and easily fed into the combustion chamber for the chemical reaction that produces thrust. Liquids and solids would require more complex storage and delivery systems, making them less practical for airplane propulsion. LPG (liquefied petroleum gas) is a type of gas and could potentially be used as an oxidizer, but it is not commonly used in airplane propulsion systems.
5.
Gasoline and air are both present in your automobile fuel tank, but combustion process does not occur because.
Correct Answer
B. There's no heat source
Explanation
The combustion process does not occur in the automobile fuel tank because there is no heat source. Combustion requires a heat source to initiate the reaction between gasoline and air, causing them to burn and release energy. Without a heat source, the gasoline and air mixture remains unburned and combustion does not take place.
6.
Flammable and combustible liquids are liquids that can burn. A liquid that ignites and burns easily at normal working temperatures is considered.
Correct Answer
B. Flammable
Explanation
The given statement states that flammable and combustible liquids are liquids that can burn. It further explains that a liquid that ignites and burns easily at normal working temperatures is considered flammable. Therefore, the correct answer is "Flammable" as it accurately describes a liquid that can easily ignite and burn at normal temperatures.
7.
It is the temperature of a fuel at which a material self-ignites without any obvious sources of ignition, such as a spark or flame.
Correct Answer
A. Auto-ignition
Explanation
Auto-ignition refers to the temperature at which a fuel can ignite spontaneously without any external ignition source. This means that the material can self-ignite without the need for a spark or flame. It is an important characteristic to consider when dealing with flammable substances, as it helps determine their safety and handling precautions.
8.
Gasoline with a flashpoint of -40°C is considered as.
Correct Answer
A. Flammable liquid
Explanation
Gasoline with a flashpoint of -40°C is considered as a flammable liquid because it has a low enough flashpoint to ignite easily when exposed to an ignition source, such as a spark or flame. Flammable liquids have a flashpoint below 37.8°C (-100°F) and can quickly vaporize, forming flammable vapors that can ignite and cause fires or explosions. Given that gasoline has a flashpoint well below this threshold, it is classified as a flammable liquid.
9.
The most common jet fuel is.
Correct Answer
D. Kerosene
Explanation
Kerosene is the most common jet fuel because it has a high energy density and a low freezing point, making it suitable for use in high-altitude and cold temperature environments. It also has a relatively low flash point, which reduces the risk of accidental ignition. Kerosene is readily available and cost-effective, making it the preferred choice for powering jet engines.
10.
Which of following fuels is used for helicopters?
Correct Answer
A. Avgas
Explanation
Avgas, short for aviation gasoline, is the correct answer because it is specifically designed for use in aircraft engines, including helicopters. It has a high octane rating to prevent engine knocking and provides the necessary power and performance required for flight operations. Diesel fuel is typically used in diesel engines, not helicopters. Octane is a measure of the fuel's resistance to knocking and is not a type of fuel itself. LPG, or liquefied petroleum gas, is commonly used as a fuel for heating and cooking, but not for helicopters.