21. The decay of timber caused by alternate wetting and drying is called
- Dry rot
- Wet rot
- Foxiness
- Doatiness
22. Annual rings of the tree represent its
- Life
- Strength
- Density
- Type
23. The outer part of the log of a timber free inside the bark which contains living cells is called
- Pith
- Medullary rays
- Sap wood
- Cambium layer
24. The advantage in using plywood is that the
- Tensile strength is equal in all directions
- Higher tensile strength in longer directions
- Higher tensile strength in shorter direction
- Lower tensile strength in longer direction
25. A short log 1.25 m or less in length is called
- Pale
- Bale
- Bolt
- Post
26. A soft negative growth that forms in wood under damp conditions is called
- Rot
- Mould
- Knot
- Checks
27. Due to attacks of dry rot, the timber
- Cracks
- Twists
- Shrinks
- Hardens
28. Plywood is made from
- Teak wood only
- Bamboo fibre
- Asbestos sheets
- Common timber
29. The most valuable timber may be obtained from
- Sal
- Re Sander
- Sandle
- Teak
30. Seasoning of timber is done for
- Change the direction of grains
- Remove voids
- Reduce moisture content
- Increase moisture content
31. Plywood has the advantage of
- Greater tensile strength in longer direction
- Greater tensile strength in shorter direction
- Same tensile strength in both directions
- None of the given answers
32. The age of tree can be known by examining
- Annular rings
- Cambium layer
- Heart wood
- Medullary rays
33. The artificial seasoning method that causes timber to become brittle and easy to break is
- Boiling
- Chemical seasoning
- Electrical seasoning
- Kiln seasoning
34. As specified in IS: 3087, the average modulus of rupture of ‘flat pressed three layer’ of Grade-I pre-laminated particle board is
- 10 N/mm2
- 15 N/mm2
- 11 N/mm2
- 12.5 N/mm2
35. Which of the following is not an objective of seasoning of timber?
- reduction of shrinkage and warpings
- reduction of weight
- increase in strength and durability
- reduction of natural defects in timber
36. A rectangular specimen is normally used for carrying out specific gravity test on timber. Dimensions of the specimen is taken as
- 5 cm x 5 cm x 15 cm
- 2 cm x 2 cm x 10 cm
- Both (a) and (b)
- Neither (a) nor (b)
37. The defect caused due to over-maturity and poor ventilation of the tree is called
- Knot
- Rind galls
- Foxiness
- heart shake
38. The wood preservative ‘creosote’ is derived from
- wood or coal
- acidic cupric chromate
- chromate zinc chloride
- pentachlorophenol
39. Which of the following are the examples of Industrial Timber?
- Veneers
- Plywood
- Block Board
- Impreg Timber
- i and ii
- i, ii and iii
- ii, iii and iv
- i, ii, iii and iv
40. A long-sawn timber piece with parallel sides having its thickness less than 50 mm and width more than 50 mm is called a/an:
- board
- end
- scantling
- plank
- log