D66 FACE THE CHALLENGE

Which process involves adding air to water to remove dissolved gases like CO2 and H2S?

• Sedimentation
• Aeration
• Filtration
• Chlorination

Answer explanation

Aeration removes dissolved gases, oxidizes iron and manganese, and improves taste and odour.

Which method is commonly used to disinfect wells in rural areas?

• Bleaching powder application
• UV treatment
• Ozone treatment
• Boiling

Answer explanation

Bleaching powder is a simple and effective method to disinfect rural wells.

Which filtration process can remove iron and manganese from water?

• Slow sand filtration
• Rapid sand filtration
• Pressure filtration with aeration
• Membrane filtration

Answer explanation

Pressure filtration combined with aeration is used to remove iron and manganese.

Which weld is used when two members meet at right angles and are joined along the edges?

• Fillet weld
• Butt weld
• Slot weld
• Plug weld

Answer explanation

Fillet welds join two surfaces at approximately right angles to each other.

What is the primary function of a gusset plate in steel structures?

• Increase load carrying capacity of bolts
• Provide lateral stability
• Connect members at a joint
• Reduce buckling

Answer explanation

Gusset plates are used to connect multiple members at a joint in trusses and frames.

Which type of footing is used for two columns with different loads and spacing?

• Rectangular footing
• Square footing
• Trapezoidal footing
• Circular footing

Answer explanation

Trapezoidal footings distribute loads from columns with unequal loads and spacing.

The lap length for tension bars in RCC should not be less than:

• 20 times bar diameter
• 40 times bar diameter
• 50 times bar diameter
• 60 times bar diameter

Answer explanation

IS codes specify that lap length in tension should be at least 40 times the bar diameter.

Which transition curve is most commonly used in highway design?

• Lemniscate
• Clothoid
• Cubic parabola
• Spiral

Answer explanation

Clothoid curves provide gradual change of curvature and are most common in highway design.

Which road surface is most suitable for high rainfall areas?

• Water bound macadam
• Bituminous concrete
• Gravel road
• Earthen road

Answer explanation

Bituminous concrete provides an impervious surface suitable for high rainfall conditions.

Which instrument is used for determining the relative height of points using a spirit bubble?

• Hand level
• Abney level
• Dumpy level
• Theodolite

Answer explanation

The dumpy level is a precise instrument for determining relative elevations.