Departmental (other) • 2026 • Paper-II
Which of the following loads has the poorest power factor?
A)
Transformer
B)
Induction motor
C)
Electric fan
D)
Induction furnace
Option D is correct: Induction furnace.
Departmental (other) • 2026 • Paper-II
Battery charging rooms must be well-ventilated primarily because the charging process produces which potentially explosive gas?
A)
Carbon dioxide
B)
Hydrogen
C)
Oxygen
D)
Nitrogen
Option B is correct: Hydrogen.
Departmental (other) • 2026 • Paper-II
Which of the following is used to reduce the earth’s resistivity?
A)
Using copper instead of GI pipe
B)
Increasing the depth of the earth electrode
C)
Adding salt and charcoal layers in the earth pit
D)
Increasing the length of the earth wire
Option C is correct: Adding salt and charcoal layers in the earth pit.
Departmental (other) • 2026 • Paper-II
What should be used to top up the electrolyte in a lead-acid battery?
A)
Tap water
B)
Distilled water
C)
Saltwater
D)
Battery acid
Option B is correct: Distilled water.
Departmental (other) • 2026 • Paper-II
Which protection device is installed to prevent the ingress of moisture and air into the transformer’s main oil tank?
A)
Buchholz relay
B)
Breather
C)
Conservator tank
D)
Explosion vent
Option B is correct: Breather.
Departmental (other) • 2026 • Paper-II
Effect of moisture on the insulating material is to:
A)
increase dielectric constant
B)
increase dielectric strength
C)
decrease insulation resistance
D)
decrease dielectric loss
Option C is correct: decrease insulation resistance.
Departmental (other) • 2026 • Paper-II
Why is electrical power transmitted at very high voltages?
A)
To minimize line losses ( I²R losses) and reduce the cost of conductors
B)
To increase the frequency of the supply
C)
To make it easier to step down for domestic use
D)
To protect transformers from lightning
Option A is correct: To minimize line losses ( I²R losses) and reduce the cost of conductors.
Departmental (other) • 2026 • Paper-II
What is the fundamental working principle of a Differential Relay used for transformer protection?
A)
It measures the impedance (Z) to the fault.
B)
It detects gas accumulation in oil-filled tanks.
C)
It compares the currents entering and leaving the protected zone.
D)
It trips when the voltage exceeds safe limits.
Option C is correct: It compares the currents entering and leaving the protected zone..
Departmental (other) • 2026 • Paper-II
Which of the following is the SI unit for electric current?
A)
Volt
B)
Ohm
C)
Ampere
D)
Watt
Option C is correct: Ampere.
Departmental (other) • 2026 • Paper-II
What happens to the secondary circuit of a Potential Transformer (PT) under normal operating conditions?
A)
It is practically short-circuited
B)
It is practically open-circuited (high impedance connected to relays/meters)
C)
It carries full-load line current
D)
It is maintained at ground potential
Option B is correct: It is practically open-circuited (high impedance connected to relays/meters).
Departmental (other) • 2026 • Paper-II
Which of the following areas should be strictly avoided when selecting a substation site?
A)
Flat terrain
B)
Areas near existing transmission lines
C)
Airports and defense establishments
D)
Agricultural land
Option C is correct: Airports and defense establishments.
Departmental (other) • 2026 • Paper-II
According to Kirchhoffs voltage law, the algebraic sum of all IR drops and e.m.fs. in any closed loop of a network is always:
A)
negative
B)
positive
C)
determined by battery e.m.fs.
D)
zero
Option D is correct: zero.
Departmental (other) • 2026 • Paper-II
Which testing method is widely recognized as the traditional “3-point method” for measuring the resistance of an existing earth electrode?
A)
Wenner Four-Pin Method
B)
Schlumberger Method
C)
Fall-of-Potential Method
D)
Clamp-on Loop Testing Method
Option C is correct: Fall-of-Potential Method.
Departmental (other) • 2026 • Paper-II
A perfect conductor has:
A)
zero conductivity
B)
unity conductivity
C)
infinite conductivity
D)
none of the above
Option C is correct: infinite conductivity.
Departmental (other) • 2026 • Paper-II
What is the approximate specific gravity of the electrolyte in a fully charged lead-acid battery?
A)
1.1
B)
1.20
C)
1.29
D)
1.5
Option C is correct: 1.29.
Departmental (other) • 2026 • Paper-II
What is the ideal/acceptable value of earth resistance for a standard electrical installation?
A)
50 Ohms
B)
25 Ohms
C)
1 Ohm
D)
100 Ohms
Option C is correct: 1 Ohm.
Departmental (other) • 2026 • Paper-II
What is the primary purpose of a power substation?
A)
To generate electrical energy
B)
To convert AC to DC power
C)
To change voltage levels and switch electrical circuits
D)
To reduce current to zero
Option C is correct: To change voltage levels and switch electrical circuits.
Departmental (other) • 2026 • Paper-II
Which devices are connected directly to the secondary of a Current Transformer?
A)
Voltmeters and potential coils of wattmeters
B)
Ammeters and current coils of wattmeters
C)
Frequency meters
D)
Power factor indicators
Option B is correct: Ammeters and current coils of wattmeters.
Departmental (other) • 2026 • Paper-II
What is the property of magnetic materials?
A)
resistivity
B)
conductivity
C)
permeability
D)
ductility
Option C is correct: permeability.
Departmental (other) • 2026 • Paper-II
Superposition theorem can be applied only to circuits having:
A)
resistive elements
B)
passive elements
C)
non-linear elements
D)
linear bilateral elements
Option D is correct: linear bilateral elements.
Departmental (other) • 2026 • Paper-II
How is a Potential Transformer (PT) connected in a power system?
A)
In series with the load
B)
In parallel with the line being measured
C)
In series-parallel
D)
Across the neutral only
Option B is correct: In parallel with the line being measured.
Departmental (other) • 2026 • Paper-II
What is the most important factor in selecting a site for a power substation?
A)
Proximity to the load center
B)
Distance from the generating station
C)
Proximity to residential areas
D)
Availability of drinking water
Option A is correct: Proximity to the load center.
Departmental (other) • 2026 • Paper-II
In electrical instruments, what is typically the most efficient form of damping?
A)
Air damping
B)
Fluid friction
C)
Eddy currents
D)
Magnetic friction
Option C is correct: Eddy currents.
Departmental (other) • 2026 • Paper-II
Why is the secondary of a current transformer (CT) always shorted under operating conditions?
A)
Protect the windings
B)
Avoid core saturation and high voltage induction
C)
Keep it safe for human beings
D)
Protect the primary circuit
Option B is correct: Avoid core saturation and high voltage induction.
Departmental (other) • 2026 • Paper-II
The earth electrode provides:
A)
Low resistance
B)
High resistance
C)
Medium resistance
D)
Very high resistance
Option A is correct: Low resistance.
