Building Materials

51. Due to attack of dry rot, the timber

1. Cracks
2. Shrinks
3. Reduces to powder
4. None of these

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52. Putty is

1. Made with finely powdered chalk and linseed oil
2. Used for fixing glass panes
3. Softened by a solution of pearl ash and quick-lime soaked in water
4. All the above

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53. Gypsum is a

1. Mechanically formed sedimentary rock
2. Igneous rock
3. Chemically precipitated sedimentary rock
4. Metamorphic rock

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54. Quick lime

1. Generates heat when added to water
2. Reacts with carbon dioxide
3. May be used for white-washing
4. All the above

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55. Quick lime is

1. Calcium carbonate
2. Calcium oxide
3. Calcium hydroxide
4. None of the above

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56. Rapid hardening cement attains early strength due to

1. Larger proportion of lime grounded finer than normal cement
2. Lesser proportion of lime grounded coarser than normal cement
3. Lesser proportion of lime grounded finer than normal cement
4. Excess percentage of gypsum

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57. Resins are

1. Not soluble in water
2. Soluble in spirit
3. Used in varnishes
4. Left behind on evaporation of oil

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58. Sand stone is

1. Sedimentary rock
2. Metamorphic rock
3. Igneous rock
4. Volcanic rock

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59. Sapwood consists of

1. Innermost annular rings around the pith
2. Portion of timber between heartwood and cambium layer
3. Thin layers below the bark
4. Thin fibre which extends from the pith outwards and holds the annular rings together

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60. Seasoning of timber is done

1. To make it water proof
2. To paint its surface
3. To increase its temperature
4. To remove water

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