DAY 20 CIVILEZY CIVILWAR KWA Paints, Plastering, Bearings

Which of the following is a desirable property of a good paint under tropical humid climate?

• High porosity

• Low elasticity

• Alkali resistance

• Brittle hard film

In stucco plastering, which of the following materials is added to improve plasticity and workability?

• Ground marble or limestone dust

• Silica sand

• Fly ash

• Quicklime

Which of the following bearings can support both axial and radial loads?

• Journal bearing

• Footstep bearing

• Thrust bearing

• Taper roller bearing

Which of the following defects in painting is primarily caused by moisture or oily surfaces under the paint film?

• Blooming

• Blistering

• Flaking

• Fading

Which statement correctly describes the role of driers in oil paints?

• They slow down the oxidation process

• They accelerate polymerisation and drying

• They act as thinners

• They provide gloss and hardness

When performing gauged plastering, the proportion of gypsum to lime is generally—

• 1 : 1 to 1 : 2

• 1 : 3 to 1 : 4

• 1 : 5

• 1 : 6

The material used for bush bearings in heavy machinery is generally —

• Cast iron

• Gunmetal

• Brass

• Lead

Which statement about lubrication in bearings is incorrect?

• Boundary lubrication occurs when oil film is very thin

• Dry lubrication uses graphite or molybdenum disulphide

• Full film lubrication prevents metal-to-metal contact

• Mixed lubrication occurs only in roller bearings

The main cause of blistering in plastered surfaces is —

• Excessive thickness of coats

• Improper curing

• Poor sand quality

• Use of hydraulic lime

In a hydrodynamic bearing, the load is supported due to —

• Metallic contact between surfaces

• Pressure generated in a lubricant film

• Elastic deformation of bearing shell

• Spring loading