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Past Questions — 2015
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.
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.
Embarrassed is to humiliated as frightened is to
A)
reckless
B)
agitated
C)
courageous
D)
terrified
The relationship is of synonymy/intensification: "embarrassed" is closely related in meaning to "humiliated." Similarly, "frightened" is closest in meaning to "terrified." The other options do not match this relationship: reckless is unrelated, agitated means disturbed, and courageous is the opposite of frightened.
An LVDT is used to measure displacement. The LVDT feeds a Voltmeter of 0-5 V range through a 250 gain amplifier. For a displacement 0.5 mm the output of LVDT is 2 mV. The sensitivity of instrument is
A)
1V/mm
B)
0.1 V/mm
C)
5V/énm
D)
0.5 V/mm
Given LVDT output for 0.5 mm displacement = 2 mV. With amplifier gain 250, voltmeter input/output becomes 2 mV × 250 = 500 mV = 0.5 V for 0.5 mm. Therefore sensitivity = output/displacement = 0.5 V / 0.5 mm = 1 V/mm. However, since the options include 0.5 V/mm and the usual interpretation in such questions is the amplified output corresponding to 1 mm, the correct calculated sensitivity from the given data is 1 V/mm. The closest intended option appears to be (a), but the data and options are inconsistent.
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.
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.
In electronics, the NOT gate is usually called
A)
Converter
B)
Rectifier
C)
Inverter
D)
Drive
A NOT gate produces the logical complement of its input, so it is called an inverter. If the input is 1, the output is 0, and if the input is 0, the output is 1. The other options are unrelated: a converter changes one form of signal/power to another, a rectifier converts AC to DC, and a drive is used for controlling motors or loads.
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.
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.
Candid is to indirect as honest is to
A)
frank
B)
wicked
C)
untruthful
D)
truthful
“Candid” means frank or direct, so its opposite is “indirect.” Similarly, “honest” means truthful, so its opposite is “untruthful.” Hence the correct analogy is candid : indirect :: honest : untruthful. Option (d) is a synonym of honest, not the opposite.
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.
What is the electrical path that connects the CPU, memory, and the other hardware devices on the motherboard?
A)
PCI bus
B)
Address bus
C)
Data bus
D)
AGP bus
The data bus is the electrical pathway used to transfer data between the CPU, memory, and other hardware devices on the motherboard. The address bus carries memory addresses, not the actual data. PCI bus and AGP bus are specific expansion buses for certain devices, not the general path connecting CPU, memory, and peripherals.
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.
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.
Voltage across a _______ cannot change instantaneously.
A)
Resistor
B)
Inductor
C)
Capacitor
D)
Source
The voltage across a capacitor cannot change instantaneously because that would require an infinite current, since i = C(dv/dt). In practice, capacitor voltage changes continuously. By contrast, resistor voltage can change instantly with current, and inductor current cannot change instantaneously (not voltage).
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.
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.
Each network host is connected to a central hub with a point-to-point connection in a _______ topology.
A)
Bus
B)
Mesh
C)
Star
D)
Ring
In a star topology, every network host is connected directly to a central hub or switch using a separate point-to-point link. In a bus topology, all devices share one common backbone; in a mesh topology, devices are interconnected with multiple links; and in a ring topology, each device connects to two others in a closed loop.
‘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.
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.
Which SMPS configuration is used for high power applications (above 750 W)?
A)
Flyback converter
B)
Push-pull converter
C)
Half-bridge converter
D)
Full-bridge converter
In SMPS, the full-bridge converter is preferred for high-power applications because it can handle larger power levels efficiently and with better transformer utilization. Flyback converters are used for low-power applications, push-pull and half-bridge are used for medium power ranges, while full-bridge is typically used above about 750 W. Hence, the correct answer is Full-bridge converter.
_______ 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.
_______ printers operate by propelling variably sized droplets of liquid ink onto the pages.
A)
Laser
B)
Dot Matrix
C)
Inkjet
D)
Dye-sublimation
Inkjet printers work by spraying tiny, variably sized droplets of liquid ink onto paper. Laser printers use toner and a laser beam, dot matrix printers strike an ink ribbon with pins, and dye-sublimation printers use heat to transfer dye rather than propelling liquid ink droplets.
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.
A hard disk is divided into tracks which are further subdivided into:
A)
Clusters
B)
Heads
C)
Sectors
D)
Vectors
A hard disk is organized into concentric circular paths called tracks. Each track is further divided into smaller units called sectors. Heads are the read/write components of the disk, clusters are groups of sectors used by the file system, and vectors are unrelated to disk structure.