SUNDAY WEEKLY EXAM (22/06/2025)

Numerical: Calculate the amount of gel water required for 400 kg of cement. Assume gel water = 15% of cement weight.

• 60 kg
• 40 kg
• 80 kg
• 100 kg

Answer explanation

Gel water = 15% of 400 kg = 0.15*400 = 60 kg.

Assertion (A): Using saline water in RCC can cause corrosion. Reason (R): Chlorides in saline water react with cement to increase strength.

• Both A and R are true and R is the correct explanation of A
• Both A and R are true but R is not the correct explanation of A
• A is true but R is false
• A is false but R is true

Answer explanation

Saline water causes corrosion due to chlorides; these do not improve strength but damage reinforcement.

Bulking of sand occurs due to:

• Presence of fine particles
• Absorption of water increasing volume
• Reduction in void ratio
• Loss of cement content

Answer explanation

Bulking occurs when moisture forms a film around particles, increasing their volume.

Obligatory points in highway alignment include:

• Only religious places and costly structures
• Only points through which road must pass
• Points through which road must or must not pass
• Only low-lying water bodies

Answer explanation

Obligatory points refer to constraints in alignment; both points to pass and to avoid.

Which component of a steel truss resists tension primarily?

• Bottom chord
• Top chord
• Diagonals
• Vertical members

Answer explanation

Bottom chord members in trusses are generally in tension and resist tensile forces.

Which process reduces sludge volume significantly?

• Sludge digestion
• Filtration
• Sedimentation
• Coagulation

Answer explanation

Digestion stabilizes organic matter and reduces volume.

Which pollutant causes blue baby syndrome?

• Nitrate
• Fluoride
• Lead
• Iron

Answer explanation

High nitrate in water is toxic for infants.

Purpose of aeration in water treatment is:

• Remove CO₂ and increase DO
• Reduce turbidity
• Increase BOD
• Reduce pH

Answer explanation

Aeration adds DO and removes volatile gases.

Which of the following is NOT a primary treatment process?

• Biological oxidation
• Screening
• Grit removal
• Sedimentation

Answer explanation

Biological oxidation occurs in secondary treatment.

Which method is used for measuring air pollutants?

• High volume sampler
• Jar test
• Turbidity meter
• pH meter

Answer explanation

High volume sampler is used for particulate matter.