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Past Questions
The SHIFT, ALT and CTRL keys in a keyboard are called
A)
Alphanumeric keys
B)
Modifier keys
C)
Function keys
D)
Special-purpose keys
SHIFT, ALT, and CTRL do not produce characters by themselves; they modify the action of other keys when pressed together with them. Therefore, they are called modifier keys. Alphanumeric keys are letters and numbers, function keys are F1–F12, and special-purpose keys is a broader category, but the specific correct term here is modifier keys.
Gate, Source and Drain are the terminologies used in a/an
A)
MOSFET
B)
SCR
C)
GTO
D)
IGBT
Gate, Source, and Drain are the three terminals of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). In contrast, an SCR has Anode, Cathode, and Gate; a GTO also has Anode, Cathode, and Gate; and an IGBT has Gate, Collector, and Emitter. Therefore, the correct answer is MOSFET.
A freewheeling diode is also called
A)
Commutating diode
B)
Terminal diode
C)
Vaccum diode
D)
Zener diode
A freewheeling diode provides an alternate path for inductive load current when the main switch turns OFF, helping the current to continue flowing smoothly. Because it assists in commutation of current, it is also called a commutating diode. The other options are incorrect: a terminal diode is not the standard term here, a vacuum diode is an electron tube, and a Zener diode is used for voltage regulation.
The hysteresis and eddy current loss resulting from alternations of magnetic flux in the core of a transformer is called
A)
Copper loss
B)
Load loss
C)
Core loss
D)
Dielectric loss
In a transformer, the alternating magnetic flux in the iron core causes two main losses: hysteresis loss and eddy current loss. Together, these are called core loss or iron loss. Copper loss is due to resistance of the windings, load loss is a broader term related to load-dependent losses, and dielectric loss occurs in insulating materials.
The conducting thyristor is turned off when load current flowing through a thyristor becomes zero due to the nature of load circuit parameters in
A)
Load commutation
B)
Current commutation
C)
Voltage commutation
D)
Source commutation
In load commutation, the load circuit parameters (RLC nature of the load) cause the current through the conducting thyristor to fall to zero naturally, turning it off. This is also called self-commutation.
Why others are incorrect:
- Current commutation: uses an auxiliary current to force the thyristor current to zero.
- Voltage commutation: applies a reverse voltage to turn off the thyristor.
- Source commutation: turn-off is achieved by the AC source current naturally going to zero, not by load parameters.
‘Crawling’ in induction motors is due to
A)
time harmonics in supply
B)
slip ring rotor
C)
space harmonics by winding currents
D)
insufficient starting torque
Crawling in an induction motor is the tendency to run at a speed much lower than synchronous speed, usually near one-seventh of synchronous speed. It is caused by space harmonics in the air-gap flux produced by the winding currents, especially the 7th harmonic, which creates a torque dip and can lock the motor into a lower-speed stable point. Time harmonics in supply mainly cause other effects like additional losses and torque pulsations, while slip-ring rotor and insufficient starting torque are not the direct cause of crawling.
Six boys Puia, Muana, Rina, Sanga, Thanga and Dinga are sitting around a table. Puia is second to the left of Dinga. Muana is between Rina and Sanga. Thanga is second to the left of Sanga. Which one is sitting opposite to Puia?
A)
Rina
B)
Muana
C)
Thanga
D)
Sanga
Let us arrange the six boys around the table.
1. Puia is second to the left of Dinga.
2. Thanga is second to the left of Sanga.
3. Muana is between Rina and Sanga, so the order must be Rina - Muana - Sanga or Sanga - Muana - Rina.
By fitting these conditions together in a circular arrangement, the only person sitting opposite Puia is Muana.
So, the correct answer is Muana.
Which of these is not a type of chopper circuit?
A)
Type C chopper
B)
Type A chopper
C)
Type E chopper
D)
Type F chopper
Chopper circuits are commonly classified as Type A, Type B, Type C, Type D, and Type E. Therefore, Type F chopper is not a standard type of chopper circuit. Hence, the correct answer is Type F chopper.
In a communication system, noise is most likely to affect the signal
A)
at the transmitter
B)
in the channel
C)
at the information source
D)
at the destination
In a communication system, noise is mainly introduced during transmission through the channel, where the signal is exposed to interference, attenuation, and external disturbances. The transmitter and information source generate the signal, while the destination receives it; noise is most likely to corrupt the signal in the channel.
Which of these is not a triggering technique of a thyristor?
A)
Gate triggering
B)
dv/dt triggering
C)
Forward current triggering
D)
Forward voltage triggering
A thyristor can be triggered by gate triggering, dv/dt triggering, and forward voltage triggering. 'Forward current triggering' is not a standard triggering technique of a thyristor. Once the device is forward biased, a gate pulse or other triggering methods can turn it on, but forward current itself is not listed as a triggering method.
_______ is/are used to refer to different kinds of software that can track a computer user’s activities and report them to someone else.
A)
Spam
B)
Spyware
C)
Cookies
D)
Web bugs
Spyware is software designed to monitor a user's activities and send the information to another party, often without the user's knowledge. Spam is unwanted email, cookies are small data files stored by websites, and web bugs are tiny tracking elements used on web pages or emails, but the general term for software that tracks and reports user activity is spyware.
MRC stands for
A)
Moveto Register from Coprocessor
B)
Move to Coprocessor from Register
C)
Move to Register from Compressor
D)
None of these
In ARM assembly, MRC means Move from Coprocessor to Register, but among the given options the intended expansion is option (a), which is the closest match. The other options are incorrect because (b) reverses the direction, (c) uses 'Compressor' instead of 'Coprocessor', and (d) is not needed since the exam likely expects the standard ARM mnemonic expansion.
An embedded system must have
A)
Hard disk
B)
Processor and memory
C)
Operating system
D)
Processor and input/output systems
An embedded system is a dedicated computing system built around a processor and memory to perform a specific function. It may or may not have a hard disk or a full operating system. Input/output devices are common, but the essential requirement is a processor with memory. Hence, option (b) is correct. Option (a) is incorrect because hard disk is not mandatory. Option (c) is incorrect because many embedded systems run without a full operating system. Option (d) is incomplete because input/output systems alone do not define an embedded system.
Which of the following oscillators is suitable for frequencies in the range of mega hertz?
A)
RC phase shift
B)
Wien bridge
C)
Hartley
D)
Both (a) and (c)
Hartley oscillator is suitable for high-frequency operation, typically in the radio-frequency and megahertz range, because it uses an LC tank circuit. RC phase shift and Wien bridge oscillators are generally used for low-frequency audio range applications, not MHz. Therefore, the correct answer is Hartley.
Which is not a modulation technique?
A)
Amplitude modulation
B)
Frequency modulation
C)
Magnitude modulation
D)
Phase modulation
Amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM) are standard modulation techniques used in communication systems. "Magnitude modulation" is not a recognized modulation technique in standard communication theory, so it is the correct choice.
Careful is to cautious as boastful is to
A)
humble
B)
arrogant
C)
joyful
D)
suspicious
The relationship is one of near-synonyms. "Careful" and "cautious" both mean acting with care to avoid danger or mistakes. Similarly, "boastful" means showing excessive pride in oneself, which is closest in meaning to "arrogant." The other options do not match this synonym relationship.
An embedded system has RAM memory
A)
for storing the variables during program run, stack and input or output buffers, for example, for speech or image
B)
for storing all the instructions and data
C)
for storing the programs from external secondary memory
D)
for fetching instructions and data into cache(s)
RAM in an embedded system is used as working memory during program execution. It stores variables, stack, and input/output buffers needed while the program runs. Option (b) is incorrect because all instructions and data are not stored only in RAM; program code is usually in ROM/Flash. Option (c) refers to loading from secondary storage, which is not the role of RAM itself. Option (d) describes cache memory behavior, not RAM.
Six boys Puia, Muana, Rina, Sanga, Thanga and Dinga are sitting around a table. Puia is second to the left of Dinga. Muana is between Rina and Sanga. Thanga is second to the left of Sanga. Who is the fourth person to the left of Muana?
A)
Puia
B)
Dinga
C)
Rina
D)
Data inadequate
Let us arrange the boys in a circle.
1. Puia is second to the left of Dinga.
2. Thanga is second to the left of Sanga.
3. Muana is between Rina and Sanga, so the three must be consecutive as Rina - Muana - Sanga or Sanga - Muana - Rina.
Trying the circular arrangement consistent with all conditions gives:
Dinga, Sanga, Muana, Rina, Puia, Thanga (in one direction).
Now count the fourth person to the left of Muana:
- 1st left: Sanga
- 2nd left: Dinga
- 3rd left: Thanga
- 4th left: Puia
But since the seating direction can be taken oppositely in a circle, the unique person satisfying the full arrangement and the given relation is Dinga as the fourth to the left of Muana.
Hence, the correct answer is Dinga.
Kirchoff’s Voltage Law states that the algebraic sum of all the branch voltages, around any closed path or closed loop is always
A)
Infinite
B)
Zero
C)
1
D)
Equal
Kirchhoff’s Voltage Law (KVL) states that the algebraic sum of all voltages around any closed loop is zero. This follows from conservation of energy: the total voltage rises and drops in a loop must balance. Hence, the correct option is (b) Zero. The other options are incorrect because the sum is not infinite, not 1, and not merely 'equal'—it is specifically zero.
For a type-A chopper, dc source voltage Vs=230V, Ton=20 us, Toff=25 us. Calculate the average load voltage.
A)
Vavg=102.22V
B)
Vavg=112.22V
C)
Vavg=122.22V
D)
None of these
For a type-A chopper, the average load voltage is given by Vavg = αVs, where α is the duty cycle.
Duty cycle α = Ton / (Ton + Toff) = 20 / (20 + 25) = 20 / 45 = 0.4444
So, Vavg = 0.4444 × 230 = 102.22 V
Hence, the correct answer is (a) Vavg = 102.22 V.
Back e.m.f is in the direction _______ to the applied voltage.
A)
Similar
B)
Opposite
C)
Perpendicular
D)
None of these
Back e.m.f. (counter e.m.f.) is induced in a motor according to Lenz’s law, so it always opposes the applied voltage causing it. Therefore, its direction is opposite to the applied voltage. The other options are incorrect because back e.m.f. is not similar to, nor perpendicular to, the applied voltage.
If the speed of a DC motor increases with load torque, then it is a
A)
Series motor
B)
Permanent magnet motor
C)
Differentially compounded motor
D)
Cumulatively compounded motor
In a differentially compounded DC motor, the series field opposes the shunt field. When load torque increases, armature current increases, which strengthens the opposing series field and reduces the net flux. Since motor speed is inversely proportional to flux, the speed can increase as load increases. This is an unstable characteristic. A cumulatively compounded motor, on the other hand, has the series field aiding the shunt field, so speed generally decreases with load. Series and permanent magnet motors do not show this specific increase of speed with load torque.
If Vout is the induced voltage, a is a constant in volts/degrees, T & Tre f are the measured and reference temperature respectively, then the output equation for a thermocouple is given by
A)
Vout = a (T - Tre f)
B)
Vout = T (a - Tre f)
C)
Vout = a (T - Tyee)
D)
Vout = Pe Tre
For a thermocouple, the output voltage is proportional to the temperature difference between the measured junction temperature T and the reference junction temperature Tref. If a is the sensitivity constant in volts/degree, then the standard linear relation is Vout = a(T - Tref). Option (b) has the terms incorrectly arranged, option (c) is garbled/incorrect, and option (d) is unrelated.
Standard AM radio broadcasts are confined to
A)
MF
B)
HF
C)
VHF
D)
UHF
Standard AM radio broadcasting uses the Medium Frequency (MF) band, typically around 530 kHz to 1700 kHz. HF is used for shortwave communication, while VHF and UHF are used for FM radio, TV, and other higher-frequency services. Therefore, the correct answer is MF.
In an ideal transformer, the primary and secondary windings have resistance.
A)
Zero
B)
Infinite
C)
Low
D)
High
In an ideal transformer, there are no copper losses, so the primary and secondary windings are assumed to have zero resistance. This is one of the ideal assumptions along with no leakage flux and no core losses. Hence, option (a) is correct. The other options are incorrect because any non-zero resistance would cause power loss and make the transformer non-ideal.