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Past Questions
Inadequate earthing in a pump house may result in:
A)
Low discharge
B)
High friction loss
C)
Pipe leakage
D)
Electric Shock
Inadequate earthing means faulty or insufficient connection of electrical equipment to the ground. In a pump house, this can cause leakage current to remain on metal parts of pumps, motors, or panels, creating a serious risk of electric shock. The other options are unrelated to earthing: low discharge and high friction loss are hydraulic issues, and pipe leakage is a plumbing/mechanical issue.
In an electrical rotating machine, the primary mechanical necessity of providing an air gap between stator and rotor is to:
A)
Reduce copper loss
B)
Improve cooling
C)
Enable rotation
D)
Improve power factor
The air gap is the small physical clearance between the stator and rotor in a rotating electrical machine. Its primary mechanical purpose is to provide space so the rotor can rotate freely without rubbing against the stator. The other options are not the main mechanical reason: copper loss is an electrical loss, cooling is a secondary benefit in some designs, and power factor is an electrical performance issue, not the main purpose of the air gap.
For starting of an induction motor in a pump house, different starters are employed depending on starting current and system conditions. Which starter applies full line voltage directly to the motor?
A)
Star-Delta starter
B)
Auto-transformer starter
C)
Soft starter
D)
Direct On Line (DOL) starter
A Direct On Line (DOL) starter connects the induction motor directly to the supply, so it applies full line voltage at starting. This gives the highest starting current, so it is used only for small motors or where the supply system can tolerate the inrush current.
Why others are incorrect:
- Star-Delta starter: starts the motor at reduced voltage in star connection, then switches to delta.
- Auto-transformer starter: applies reduced voltage through a tapped autotransformer during starting.
- Soft starter: gradually increases the voltage using power electronics to limit starting current and mechanical stress.
Which item is measured in cubic metres?
A)
Earthwork excavation
B)
Brick masonry
C)
Plastering
D)
Painting
Earthwork excavation is commonly measured in cubic metres (m³) because it involves volume. Brick masonry is also generally measured in cubic metres, but in standard single-answer MCQs of this type, earthwork excavation is the expected answer as the most typical volumetric item. Plastering and painting are measured in square metres (m²) because they involve surface area.
Analysis of rates is carried out to determine:
A)
Cost of construction
B)
Water quality
C)
Soil strength
D)
Population
Analysis of rates is used in estimation and costing to find the unit cost of an item of work by considering materials, labour, equipment, overheads, and profit. Therefore, its purpose is to determine the cost of construction. Water quality, soil strength, and population are unrelated to rate analysis.
Rainwater harvesting primarily aims to:
A)
Increase wastewater generation
B)
Conserve water resources
C)
Increase runoff
D)
Reduce evaporation
Rainwater harvesting is the collection and storage of rainwater for later use or for groundwater recharge. Its main purpose is to conserve water resources by reducing dependence on external water sources and improving water availability. Option (a) is incorrect because it does not increase wastewater generation. Option (c) is incorrect because harvesting aims to reduce runoff, not increase it. Option (d) may happen indirectly in some systems, but it is not the primary aim.
The most common material used for septic tank construction is:
A)
Timber
B)
Steel sheet
C)
RCC
D)
Plastic
Septic tanks are commonly constructed using Reinforced Cement Concrete (RCC) because it is strong, durable, waterproof when properly built, and suitable for underground sewage storage. Timber is unsuitable due to decay, steel sheet is prone to corrosion, and plastic is used only in some prefabricated systems, not as the most common material.
HDPE pipes are preferred because they are:
A)
Corrosion resistant
B)
Brittle
C)
Heavy
D)
Expensive
HDPE (High-Density Polyethylene) pipes are widely preferred in water supply and piping systems because they do not corrode like metal pipes. They are also lightweight, flexible, and durable. The other options are incorrect: HDPE pipes are not brittle, not heavy, and are generally cost-effective rather than expensive.
If the contact resistance of a circuit breaker is high, the immediate risk is:
A)
Nuisance tripping
B)
Excessive heating
C)
Incorrect settings
D)
Reduced capacity
High contact resistance in a circuit breaker causes extra power loss at the contacts, which is dissipated as heat. This can quickly lead to overheating, insulation damage, contact deterioration, and even failure. Nuisance tripping, incorrect settings, and reduced capacity are not the immediate direct effect of high contact resistance.
RCC stands for:
A)
Reinforced Clay Concrete
B)
Ready Cement Concrete
C)
Reinforced Concrete Column
D)
Reinforced Cement Concrete
RCC is the standard abbreviation for Reinforced Cement Concrete, a composite material in which steel reinforcement is embedded in concrete to improve tensile strength. The other options are incorrect because RCC does not mean Reinforced Clay Concrete, Ready Cement Concrete, or Reinforced Concrete Column.
Which of the following protective relays is most sensitive to ground faults in a power system?
A)
Overcurrent relay
B)
Under-voltage relay
C)
Thermal overload relay
D)
Earth fault relay
An earth fault relay is specifically designed to detect ground (earth) faults and is therefore the most sensitive relay for this purpose. It operates on small residual or zero-sequence currents that appear when insulation fails and current flows to earth.
Why others are incorrect: Overcurrent relay responds to excessive current in general but is not as sensitive specifically to ground faults. Under-voltage relay operates when voltage drops below a set value, not primarily for fault-to-ground detection. Thermal overload relay protects against overheating due to overload, mainly in motors and equipment, not ground faults.
Biodegradable waste includes:
A)
Plastic
B)
Glass
C)
Food waste
D)
Metal
Biodegradable waste is waste that can be broken down naturally by microorganisms, such as bacteria and fungi. Food waste decomposes easily, so it is biodegradable. Plastic, glass, and metal do not decompose naturally in this way, so they are non-biodegradable.
The detention period of a septic tank is generally:
A)
2–4 hours
B)
5 days
C)
24–48 hours
D)
10 days
The detention period of a septic tank is the time sewage is retained in the tank for sedimentation and anaerobic digestion. In general design practice, it is about 24–48 hours.
Why others are incorrect:
- (a) 2–4 hours: too short for effective settling and digestion.
- (b) 5 days: much longer than the usual septic tank detention period.
- (d) 10 days: far too long for normal septic tank design.
Hand Pump Tube Wells are mainly used for:
A)
Irrigation
B)
Hydropower
C)
Navigation
D)
Rural water supply
Hand pump tube wells are shallow or medium-depth wells fitted with a manual pump, mainly intended to supply drinking water in villages and small rural settlements where piped water systems may not be available. इसलिए the correct answer is rural water supply.
Why others are incorrect:
(a) Irrigation: Tube wells for irrigation usually require higher discharge and are generally power-operated, not hand pumps.
(b) Hydropower: Hand pump tube wells have no role in power generation.
(c) Navigation: They are unrelated to transport or waterways.
Diseases transmitted through insects are called:
A)
Water-borne diseases
B)
Air-borne diseases
C)
Vector-borne diseases
D)
Food poisoning
Option C is correct: Vector-borne diseases.
Biogas plants mainly produce:
A)
Oxygen
B)
Nitrogen
C)
Carbon monoxide
D)
Methane gas
Option D is correct: Methane gas.
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.
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.
Water having pH less than 7 is considered:
A)
Neutral
B)
Alkaline
C)
Hard
D)
Acidic
Option D is correct: Acidic.
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.
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.
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.
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.