This set of Building Construction Multiple Choice Questions & Answers (MCQs) focuses on “Timber”.
1. Which of the following defects occur in the seasoning process of wood?
b) Brown rot
c) Sap stain
d) Blue stain
Explanation: Bow is a defect that occurs in the seasoning process of wood and is indicated by the curvature which forms in the direction of the length of timber. Blue stain, sap stain and brown rot are the defects caused in timber by fungi.
2. Dry rot is a defect caused in timber in which wood is converted into dry powder form by fungi. Which of the following statements about dry rot is not correct?
a) Unseasoned softwoods cannot be easily attacked by dry rot
b) It usually occurs at places where there is no free circulation of air
c) If the storage of timber after its felling is not done properly, it is liable for the attack of dry rot
d) It is not essential to have damp conditions for the development of dry rot
Explanation: Dry rot is a defect caused in timber in which wood is converted into dry powder form by fungi. It usually occurs at those places where the free circulation of air is absent. It is found that unseasoned softwoods are easily attacked by dry rot.
3. Chir and deodar are examples of hardwoods while oak and sal are examples of softwoods.
Explanation: Chir and deodar are examples of softwoods while oak and sal are examples of hardwoods. The terms hardwoods and softwoods have commercial importance only.
4. When a part of the timber is affected by dry rot, the unaffected portion of the timber should be painted with a solution of _________
a) Aluminium nitrate
b) Silver chloride
c) Copper sulphate
d) Lead acetate
Explanation: When a portion of the timber is affected by dry rot, the left out portion which is not affected should be painted with copper sulphate solution. While that portion of the timber which is affected and damaged due to dry rot should be completely taken out.
5. Which of the following is not a variety of industrial timber?
Explanation: Timber that is scientifically prepared in a factory is called industrial timber. There are different varieties of industrial timber. These are veneers, plywood, fibreboard, impreg timbers and compreg timbers.
6. Batten is a piece of timber whose thickness and breadth do not exceed ________
a) 10 mm
b) 30 mm
c) 50 mm
d) 100 mm
Explanation: Timber is available in markets in various forms. These are battens, boards, ends, poles, etc. Batten is a piece of timber whose thickness and breadth do not exceed 50 mm.
7. Which of the following statements about plywood is not true?
a) Plywoods are available in large sizes
b) They are elastic
c) Expansion and shrinkage are very high
d) Plywoods are light in weight
Explanation: Plywoods are light in weight. They are elastic and are available in large sizes. Expansion and shrinkage are relatively very low as plies are placed at an angle of 90° to each other.
8. The maximum limit of weight of fibreboards is _________
a) 960 kg/m3
b) 1960 kg/m3
c) 2460 kg/m3
d) 2960 kg/m3
Explanation: Fibreboards are rigid boards. They are also known as reconstructed wood. The maximum limit of weight of fibreboards is 960 kg/m3. The weight depends on the pressure applied during their manufacturing.
9. Which of the following is available under trade names such as Formica, Sunmica, Sungloss etc?
c) Impreg timber
d) Compreg timber
Explanation: Impreg timber is available under trade names such as Formica, Sunmica, Sungloss, etc. It is the timber that is partly or fully covered with resin. Impreg timber is strong and durable.
10. Timber which is mostly used for engineering purposes belongs to endogenous trees.
Explanation: Timber which is mostly used for engineering purposes belongs to exogenous trees. These trees are further divided into two groups – deciduous and conifers. However, timber from endogenous trees has very limited engineering applications.
Sanfoundry Global Education & Learning Series – Building Construction.
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