D55 MASTER THE DAY

Which type of sewage includes rainwater collected from streets and roofs?

• Industrial sewage
• Storm sewage
• Sanitary sewage
• Septic sewage

Answer explanation

Storm sewage is surface runoff collected during and immediately after rain.

Which pipe is specifically used to carry discharge from toilets?

• Vent pipe
• Subsoil pipe
• Soil pipe
• Rainwater pipe

Answer explanation

Soil pipe is used to carry human waste from toilets.

What is the primary source of drinking water supply in most cities?

• Groundwater
• Surface water
• Rainwater harvesting
• Desalinated water

Answer explanation

Surface water sources like rivers and lakes are common in city water supply.

Which waste is offensive and contains 0.1% solids?

• Sludge
• Garbage
• Sewage
• Rubbish

Answer explanation

Sewage is mostly water with 0.1% solids and has a foul odor.

Which item listed below is part of inorganic refuse?

• Tree leaves
• Mud
• Excreta
• Fruit peels

Answer explanation

Inorganic or non-combustible refuse includes mud, dust, and metals.

Which method of population forecasting assumes a constant rate of increase?

• Arithmetic method
• Geometric method
• Incremental method
• Graphical method

Answer explanation

Geometric method assumes a constant percentage increase.

Which of the following is a cause of variation in water demand?

• Population size
• Quality of water
• Climate
• All of the above

Answer explanation

All these factors affect water consumption patterns.

The total water requirement for public use is restricted to what percentage of total demand?

• 20%
• 15%
• 10%
• 5%

Answer explanation

Water for public use is restricted to 5–10% as per standards.

Which part of a sewer cross-section is called the 'crown'?

• Bottom-most point
• Topmost point
• Midpoint
• Invert level

Answer explanation

The crown is the topmost inner point of a sewer pipe.

What is the name of the component that prevents loss of water seal in plumbing traps?

• Air gap
• Anti-syphonage pipe
• Vent pipe
• Backflow valve

Answer explanation

Anti-syphonage pipes prevent loss of trap seals due to pressure differences.