Explanation: Reliability of a material is important to maintain the quality of the material. The material has to be manufactured by a standard manufacturer that produces good quality material to ensure that the material is not easily damaged.

Explanation: The availability of material is an economic consideration. The material being used for the construction of an aircraft must be available for all requirements. Structure and appearance are physical properties of a material.

Explanation: Porosity is the quantity of void space present in the structure of a material. It is the ratio of pore volume to the total structure volume. It is one of the physical properties of a material.

Explanation: A material that requires supplementary operations before being used in manufacturing is called supplementary operational requirement. The operations vary depending on the material. A few examples are plating, heat treatment etc. The materials cannot be used in their natural state. This is a disadvantage as it is more costly and time-consuming.

Explanation: Castability is a technological factor of materials. The ease with which the material can be cast is called castability. The higher the castability, easier the process. Melting point and availability are physical properties of a material.

Explanation: The dimension of a material is a physical property. Dimension is the physical measurement of an object. Length, breadth and height describe the dimensions of an object. It is not an economic, technological or mechanical property.

Explanation: Cost should not be the only and primary consideration in the selection of materials. The materials that have good properties like high strength /weight ratio must be selected, and cost can be a factor of selection among them later in the process. The quality of material must not be compromised due to cost.

Explanation: The capability to produce foam is called the foamability of a material. The ability of a material to be made into soldered joints easily is called solderability of a material. Both foamability and solderability are technological factors of a material.

Explanation: Standardization of materials is an advantage. It refers to using the available material in manufacturing different components, instead of stocking several materials that result in residual materials being left.

Explanation: Color is the least considered factor in the selection of materials. The technological, physical and economic factors like melting point, weldability and availability are much more important as they affect safety and performance more. Also, materials can be colored according to requirements.

Explanation: Machinability is the ease of cutting material. It is the change in the form of material along with being economically beneficial, at a low cost. The machinability of a material is a technological factor.

Explanation: While considering the cost of shop equipment required, both the maintenance cost plus the initial cost of the material must be considered. This is an important economic consideration in the selection of materials used in the construction of an aircraft.