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Past Questions
Controlled tipping is also known as:
A)
Incineration
B)
Composting
C)
Sanitary landfill
D)
Pulverization
Option C is correct: Sanitary landfill.
Rainwater harvesting primarily aims to:
A)
Increase wastewater generation
B)
Conserve water resources
C)
Increase runoff
D)
Reduce evaporation
Option B is correct: Conserve water resources.
Which demand is considered while designing fire hydrant systems?
A)
Industrial demand
B)
Commercial demand
C)
Fire demand
D)
Institutional demand
Option C is correct: Fire demand.
The arithmetic increase method of population forecasting assumes:
A)
Constant percentage growth
B)
Sudden growth
C)
Constant numerical increase
D)
Negative growth
Option C is correct: Constant numerical increase.
Which ingredient in concrete acts as a binding material?
A)
Sand
B)
Aggregate
C)
Water
D)
Cement
Option D is correct: Cement.
Biogas plants mainly produce:
A)
Oxygen
B)
Nitrogen
C)
Carbon monoxide
D)
Methane gas
Option D is correct: Methane gas.
Rainwater harvesting is useful for:
A)
Increasing runoff
B)
Flooding roads
C)
Groundwater recharge and water conservation
D)
Soil erosion
Option C is correct: Groundwater recharge and water conservation.
Which reinforcement is mainly provided in a cantilever beam?
A)
Bottom reinforcement
B)
Side reinforcement
C)
Spiral reinforcement
D)
Top reinforcement
Option D is correct: Top reinforcement.
Segregation in concrete means:
A)
Proper mixing
B)
Increase in workability
C)
Separation of coarse aggregate from mortar
D)
Reduction in cement content
Option C is correct: Separation of coarse aggregate from mortar.
In a sedimentation tank, detention time is provided for:
A)
Disinfection
B)
Filtration
C)
Settling of suspended particles
D)
Aeration
Option C is correct: Settling of suspended particles.
Water having pH less than 7 is considered:
A)
Neutral
B)
Alkaline
C)
Hard
D)
Acidic
Option D is correct: Acidic.
Turbidity in water is mainly caused by:
A)
Dissolved gases
B)
Suspended particles
C)
Hardness
D)
Chlorides
Option B is correct: Suspended particles.
The minimum thickness of RCC water tank wall is generally provided to:
A)
Improve appearance
B)
Reduce dead load
C)
Ensure water tightness and durability
D)
Reduce cement content
Option C is correct: Ensure water tightness and durability.
The process of removing entrapped air from fresh concrete is called:
A)
Mixing
B)
Transportation
C)
Compaction
D)
Finishing
Option C is correct: Compaction.
Hand Pump Tube Wells are mainly used for:
A)
Irrigation
B)
Hydropower
C)
Navigation
D)
Rural water supply
Option D is correct: Rural water supply.
The main purpose of a service reservoir is:
A)
Water treatment
B)
Storage and distribution
C)
Pumping
D)
Filtration
Option B is correct: Storage and distribution.
The structure used to collect water from a river is called:
A)
Reservoir
B)
Aqueduct
C)
Intake
D)
Weir
Option C is correct: Intake.
Which factor increases domestic water consumption?
A)
Low standard of living
B)
Dry climate only
C)
Improved sanitation facilities
D)
Small population
Option C is correct: Improved sanitation facilities.
Sullage water does NOT include:
A)
Bathroom waste water
B)
Kitchen waste water
C)
Wash basin discharge
D)
Human excreta
Option D is correct: Human excreta.
Which chemical is commonly used for water disinfection?
A)
Alum
B)
Lime
C)
Chlorine
D)
Soda
Step-by-step reasoning:
1. **Disinfection** is the process of killing pathogenic microorganisms (bacteria, viruses, and protozoa) in water to make it safe for human consumption.
2. **Chlorine (Option c)** is the most widely used chemical for disinfection globally. It acts as a powerful oxidizing agent that penetrates the cell walls of microorganisms, disrupting their enzymatic activity and killing them. It also provides a 'residual effect,' meaning it continues to protect the water from re-contamination as it travels through the distribution system.
3. **Alum (Option a)**, or Aluminum Sulfate, is used as a 'coagulant' in water treatment. It helps in removing turbidity by clumping small particles together into larger flocs, but it does not disinfect the water.
4. **Lime (Option b)**, or Calcium Hydroxide, is primarily used for 'water softening' (removing hardness) and pH adjustment to prevent corrosion in pipes.
5. **Soda (Option d)**, usually referring to Soda Ash (Sodium Carbonate), is also used for water softening and pH stabilization, not for disinfection.
GI pipes are mainly:
A)
Plastic pipes
B)
Galvanized Iron pipes
C)
Cement pipes
D)
Copper pipes
The term 'GI' is a standard engineering abbreviation for 'Galvanized Iron'. Galvanization is the process of applying a protective zinc coating to iron or steel to prevent rusting and corrosion. In piping materials, GI pipes are widely used for water supply and plumbing due to their strength and corrosion resistance.
Analysis of other options:
- Option (a) Plastic pipes: These include materials like PVC, HDPE, or CPVC, which are polymers, not iron.
- Option (c) Cement pipes: These are made from concrete or asbestos-cement and are typically used for sewage or large-scale water mains.
- Option (d) Copper pipes: These are made from pure copper and are distinct from iron-based materials.
Pump efficiency is ratio of:
A)
Output heat/Input heat
B)
Output discharge/Input discharge
C)
Output power/Input power
D)
Output head/pipe length
Pump efficiency (η) is a measure of how effectively a pump converts mechanical energy (input) into hydraulic energy (output).
1. **Water Power (Output Power):** This is the useful power delivered to the fluid, calculated as P_out = ρ × g × Q × H (where ρ is density, g is gravity, Q is discharge, and H is head).
2. **Brake Power (Input Power):** This is the power supplied to the pump shaft by the motor or engine (P_in).
3. **Efficiency Formula:** Efficiency is defined as the ratio of the useful power output to the total power input: η = (Output Power / Input Power) × 100%.
Why other options are incorrect:
- Option (a): Pumps are mechanical devices for moving fluids, not heat exchangers; heat is a loss (inefficiency), not the intended output.
- Option (b): Discharge is the volume flow rate. Input and output discharge are generally the same (minus leaks), and their ratio does not define efficiency.
- Option (d): Head is a measure of pressure/height, and pipe length is a physical dimension; their ratio is not a measure of efficiency.
Which concrete grade is minimum for RCC work?
A)
M10
B)
M15
C)
M20
D)
M25
According to IS 456:2000 (the Indian Standard code of practice for Plain and Reinforced Concrete), the minimum grade of concrete for Reinforced Cement Concrete (RCC) work depends on the exposure conditions. For 'Mild' exposure conditions, the minimum grade of concrete specified for RCC is M20. Grades below M20 (such as M10 and M15) are generally used for Plain Cement Concrete (PCC) or lean concrete work and are not permitted for structural RCC elements because they do not provide sufficient strength and durability to protect the reinforcement from corrosion. While higher grades like M25 are used for more severe exposure conditions, M20 remains the absolute baseline minimum for any RCC work under standard conditions.
Rainwater harvesting primarily helps in:
A)
Flood control
B)
Groundwater recharge
C)
Surface runoff increase
D)
Soil erosion
Rainwater harvesting (RWH) is the process of collecting, filtering, and storing rainwater for future use or directing it into the ground to replenish aquifers.
1. Why 'b' is correct: The primary objective of RWH is to capture precipitation that would otherwise run off and allow it to infiltrate the soil, thereby raising the water table and recharging groundwater reserves. This is critical for sustainable water management, especially in regions facing water scarcity.
2. Why 'a' is incorrect: While RWH can reduce the volume of peak runoff during heavy rain, its primary purpose is water conservation and supply, not large-scale flood control (which typically requires dams, levees, and storm drains).
3. Why 'c' is incorrect: RWH aims to *decrease* surface runoff by capturing the water, not increase it. Increasing runoff leads to wastage of water and higher risks of flooding.
4. Why 'd' is incorrect: Soil erosion is caused by uncontrolled surface runoff washing away topsoil. RWH helps *prevent* soil erosion by reducing the velocity and volume of runoff, rather than promoting it.
Which footing is provided for a single column?
A)
Raft footing
B)
Combined footing
C)
Isolated footing
D)
Pile footing
Step-by-step reasoning:
1. Definition of Footing: A footing is the lower part of a foundation that spreads the load of the structure over a larger area of soil to prevent shear failure or excessive settlement.
2. Analysis of Options:
- Isolated Footing: This is a type of shallow foundation used to support a single column. It is the most economical and common choice when the soil bearing capacity is sufficient and columns are spaced far apart.
- Combined Footing: This is used when two or more columns are so close together that their isolated footings would overlap, or when a column is near a property line.
- Raft (Mat) Footing: This is a large continuous slab that supports all the columns and walls of a building, used when the soil is weak or the column loads are very high.
- Pile Footing: This is a deep foundation used to transfer loads to a deeper, stronger soil layer or rock when the surface soil is incapable of supporting the load.
3. Conclusion: Since the question specifically asks for a footing provided for a 'single column', the correct answer is the Isolated footing.