ELECTRICAL ENGINEERING PAST PAPERS AND SYLABUS
Electrician
Show Answers
چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
All poles have positive real parts
All poles lie in the right half of the s-plane
All poles have negative real parts
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
For a linear control system , stability requires that all poles of its characteristic equation lie in the left half of the s-plane (negative real parts) .
Poles with negative real parts ensure that system responses decay over time, preventing unbounded output.
Root locus
Routh-Hurwitz criterion
Bode plot
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
The Routh-Hurwitz criterion determines system stability by analyzing the location of poles in the s-plane without explicitly calculating them.
It provides a systematic way to check if all poles have negative real parts, ensuring a stable control system .
Lenz's law
Faraday's law
Ampere's circuital law
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Ampere’s circuital law relates the magnetic field around a closed loop to the total current passing through the loop .
It is fundamental in calculating magnetic fields in current-carrying conductors and designing electromagnets .
BJT
MOSFET
SCR
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Silicon Controlled Rectifiers (SCRs) can handle high voltage and current, making them ideal for high-power rectification .
They allow controlled conduction in one direction.
They are widely used in power conversion and industrial applications .
Directional protection
Overvoltage protection
Differential protection
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Differential protection compares currents entering and leaving a transformer; any difference indicates an internal fault .
It provides fast and selective isolation of the transformer, minimizing damage and service interruption .
Thermal relay
Distance relay
Differential relay
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Distance relays detect faults by measuring the impedance between the relay location and the fault .
If the impedance falls below a set threshold, indicating a nearby fault , the relay operates to isolate the affected section .
Store electrical energy
Generate electricity
Detect faults
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Protective relays monitor electrical parameters and identify abnormal conditions such as overcurrent or short circuits .
They trigger circuit breakers to isolate faulty sections, preventing damage to equipment and ensuring system safety .
Field winding
Commutator
Armature
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
The armature of a DC machine carries current and interacts with the magnetic field to produce torque.
This torque converts electrical energy supplied to the machine into mechanical rotational energy.
To amplify the signal
To convert digital to analog
To impress information
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
A modulator encodes the information signal onto a carrier wave for effective transmission over a communication channel .
This allows signals to travel long distances without significant loss or interference .
Inductor
Transformer
Circuit breaker
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Circuit breakers automatically interrupt the flow of current when it exceeds a safe limit, protecting equipment and wiring .
They are essential safety devices in power distribution systems to prevent damage from overcurrent or short circuits.