Explanation

• Rabi crops are sown in winter (October–December) and harvested in spring (March–April).
• Wheat is the major Rabi crop, especially in Pakistan and India.

Additional information:

• Kharif crops are sown in summer (April–June) and harvested in autumn (September–October).
• Rice is the major Kharif crop, grown during the monsoon season.

Last verified on 24-05-2026

Explanation

The minimum concrete cover protects reinforcement from corrosion and fire.

According to standards, it should not be less than 8 mm for reinforced concrete structures.

Explanation

Coarse-grained soils (like sand and gravel) are best compacted using vibratory rollers due to their density.

Vibrations help particles settle tightly, increasing soil strength and stability.

Explanation

Vicat apparatus measures the initial and final setting time of cement paste.

It ensures the cement has proper workability and hardening characteristics.

Explanation

1 UK (long) ton is defined as 2240 pounds, which equals approximately 1016 kg.

It is slightly heavier than the US (short) ton, which is 907.18 kg.

Explanation

Ferrous oxide (FeO) in OPC contributes to the strength and setting properties of cement.

Its typical proportion is low, around 2–4%, to maintain proper clinker chemistry.

Explanation

Lime is classified as rich, poor, and hydraulic based on its calcium content and setting properties.

Hydraulic lime can set under water due to the presence of silica and alumina.

Explanation

Specific weight (γ) is weight per unit volume; for water, γ ≈ 9.81 kN/m³.

It is derived from γ = ρ × g, where ρ = 1000 kg/m³ and g = 9.81 m/s².

Explanation

DWV pipes are used to remove wastewater and provide ventilation in plumbing systems.

They prevent siphoning of traps and maintain proper flow in drainage systems.

Explanation

Tubemills are used for finishing or dressing steel bars and rods to required dimensions and smoothness.

They ensure uniform size and surface quality for construction purposes.