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Past Questions — 2016
A fully controlled thyristor bridge drives a DC motor. The system is capable of
A)
Motoring & braking in both directions
B)
Only motoring in both directions, no braking
C)
Only motoring in forward directions, no braking
D)
None of these
A fully controlled thyristor bridge can provide both positive and negative average DC output voltage by varying the firing angle. In a DC motor drive, this allows operation in all four quadrants when combined with appropriate current direction control: motoring and regenerative braking in both forward and reverse directions. Hence, the system is capable of motoring and braking in both directions. Options (b) and (c) are incorrect because they limit the drive to motoring only, and (d) is therefore also incorrect.
Power factor of magnetizing component of current of a transformer is
A)
0.8 lag
B)
0.8 lead
C)
Zero
D)
Unity
In a transformer, the magnetizing component of current is the reactive part that produces the alternating magnetic flux in the core. Since it is 90° out of phase with the voltage, its power factor is cos 90° = 0. Therefore, the power factor of the magnetizing component is zero. The other options are incorrect because 0.8 lag/lead and unity correspond to currents having real power component, which the pure magnetizing current does not have.
When installing PCI NICs one can check IRQ availability by looking at
A)
Dip switch
B)
CONFIGSYS
C)
Jumper setting
D)
Motherboard BIOS
PCI network interface cards (NICs) usually use Plug and Play, so IRQ assignments are handled automatically by the system BIOS. To check IRQ availability, you look in the motherboard BIOS settings. Dip switches and jumper settings are typical of older hardware, and CONFIG.SYS is a DOS configuration file, not the place to check PCI IRQ availability.
The scale of voltmeter is uniform. Its type is
A)
Moving iron
B)
Induction
C)
Moving coil permanent magnet
D)
Moving coil dynamometer
A voltmeter with a uniform scale is typically a PMMC (permanent magnet moving coil) type instrument. In a PMMC instrument, deflection is proportional to current, so the scale is evenly spaced.
Why others are incorrect:
- Moving iron instruments have a non-uniform scale.
- Induction instruments are generally used for AC and do not give a uniform scale for this purpose.
- Moving coil dynamometer type instruments are also not known for a uniformly spaced scale like PMMC.
Therefore, the correct answer is moving coil permanent magnet.
The image (second) channel selectivity of a super heterodyne communication receiver is determined
A)
Antenna and pre-selector
B)
The preselector and RF amplifier
C)
The pre selector and IF amplifier
D)
The RF and IF amplifier
In a superheterodyne receiver, image-channel selectivity is achieved mainly before and at the first frequency conversion stage. The preselector rejects unwanted image frequencies at the input, and the IF amplifier provides the main tuned selectivity at the intermediate frequency. The antenna alone does not provide sufficient selectivity, and the RF amplifier mainly improves sensitivity rather than image rejection. Hence, the correct choice is the preselector and IF amplifier.
A thermocouple is a transducer
A)
Variable resistance
B)
Voltage generating
C)
Variable inductance
D)
Voltage divider
A thermocouple works on the Seebeck effect: when two dissimilar metals are joined and their junctions are at different temperatures, an EMF is produced. Therefore, it is a self-generating transducer that converts temperature into voltage. It is not a variable resistance, variable inductance, or voltage divider device.
The additional duplicate register used in ARM machines are called as
A)
Copied-registers
B)
Banked registers
C)
Extra registers
D)
Extential registers
In ARM architecture, some registers are duplicated for different operating modes (such as user, FIQ, IRQ, supervisor) so that interrupt handling and mode switching are faster. These duplicated registers are called banked registers. The other options are not standard ARM terminology.
Which of the following best describes static memory devices?
A)
Semiconductor memory devices in which stored data is retained as long as power is applied.
B)
Semiconductor memory devices in which stored data will not be retained with the power applied unless constantly refreshed
C)
Memory devices that are magnetic in nature and do not require constant refreshing
D)
Memory devices that are magnetic in nature and require constant refreshing
Static memory (SRAM) retains stored data so long as power is supplied, without needing refresh cycles. This is the key difference from dynamic memory (DRAM), which must be constantly refreshed to preserve data. Options (b), (c), and (d) describe dynamic memory or magnetic storage incorrectly. Static memory is semiconductor-based, not magnetic.
Each instruction in ARM machines is encoded into Word.
A)
2 byte
B)
3 byte
C)
4 byte
D)
8 byte
ARM uses fixed-length instructions in its classic ARM state, and each instruction is encoded in one word. In ARM architecture, a word is 32 bits = 4 bytes. Therefore, each instruction is encoded into 4 bytes. The other options are incorrect because 2 bytes = half-word, 3 bytes is not a standard word size, and 8 bytes = double word.
A GTO thyristor
A)
Requires a special turn-off circuit like a thyristor
B)
Can be turned off by removing the gate pulse
C)
Can be turned off by a negative current pulse at the gate
D)
Can be turned off by a positive current pulse at the gate
A GTO (Gate Turn-Off) thyristor is a special type of thyristor that can be turned ON by a positive gate current and turned OFF by applying a negative gate current pulse. This negative gate current extracts carriers from the device and forces commutation. Option (a) is incorrect because a GTO does not require a separate turn-off circuit like a conventional thyristor. Option (b) is incorrect because simply removing the gate pulse cannot turn it off. Option (d) is incorrect because a positive gate current is used for turn-on, not turn-off.
The power consumed in a circuit element will be least when the phase difference between current & voltage is
A)
180°
B)
90°
C)
60°
D)
0°
Power in an AC circuit element is given by P = VI cos\u03c6, where \u03c6 is the phase difference between voltage and current. For a given V and I, the power is least when cos\u03c6 is minimum. At \u03c6 = 90\u00b0, cos\u03c6 = 0, so the average power consumed is zero, which is the least possible value. At 0\u00b0 power is maximum, at 60\u00b0 it is positive, and at 180\u00b0 the power expression becomes negative for the instantaneous sign convention, not the least consumed in the usual average-power sense.
In RLC circuits, the current at resonance is
A)
Maximum in parallel resonance and minimum in series resonance
B)
Maximum in series resonance and minimum in parallel resonance
C)
Maximum in both series & parallel resonance
D)
Minimum in both series & parallel resonance
In a series RLC circuit at resonance, the inductive and capacitive reactances cancel, so the impedance becomes minimum and the current is maximum. In a parallel RLC circuit at resonance, the circuit impedance becomes maximum, so the supply current is minimum. Therefore, the current is maximum in series resonance and minimum in parallel resonance.
In a DC chopper, for periodic time T, the output voltage can be controlled by FM by varying
A)
T keeping Ton constant
B)
Ton keeping T constant
C)
T keeping Toff constant
D)
Toff keeping T constant
In frequency modulation (FM) control of a DC chopper, the on-time Ton is kept constant and the period T is varied. Since duty ratio D = Ton/T, changing T changes the average output voltage. Option (b) describes time-ratio control, not FM. Options (c) and (d) are not the standard FM method for chopper output control.
The main importance of ARM micro-processors is providing operation with,
A)
Low cost and low power consumption
B)
Higher degree of multi-tasking
C)
Lower error or glitches
D)
Efficient memory management
ARM microprocessors are widely used because they are designed for energy efficiency and low manufacturing cost. Their architecture is optimized for low power consumption, making them suitable for mobile devices, embedded systems, and battery-operated equipment. The other options are not the main defining advantage of ARM: multitasking depends more on the operating system, memory management is not their primary selling point, and lower glitches is not a standard characteristic used to describe ARM processors.
A hard disk is divided into tracks which are further subdivided into
A)
Cluster
B)
Sectors
C)
Vectors
D)
Heads
A hard disk is organized into circular tracks. Each track is further divided into smaller units called sectors. A cluster is a group of sectors, vectors are unrelated to disk structure, and heads are the read/write components of the disk, not subdivisions of tracks.
___ refers to the physical or logical arrangement of a network.
A)
Data flow
B)
Mode of operation
C)
Topology
D)
None of these
Network topology refers to the physical or logical arrangement of a network, including how devices are connected and how data moves between them. Data flow describes how data travels, and mode of operation refers to how a device/system functions, not the network’s arrangement.
ARM stands for .
A)
Advanced Rate Machines
B)
Advanced RISC Machines
C)
Artificial Running Machines
D)
Aviary Running Machines
ARM is the acronym for Advanced RISC Machines. It refers to a family of processor architectures based on the RISC (Reduced Instruction Set Computer) design philosophy. The other options are not the standard expansion of ARM.
When installing a SCSI CD-ROM drive, one must set the CD-ROM SCSI adapter to
A)
B0007
B)
An unused SCSI address
C)
The same address as the SCSI device before the CD-ROM
D)
SCSI ID=1
A SCSI device must have a unique SCSI ID on the bus. When installing a SCSI CD-ROM drive, the adapter/device should be configured to an unused SCSI address so it does not conflict with any existing SCSI device. Option (c) is wrong because two devices cannot share the same SCSI ID. Option (d) is too specific and not universally required, since the correct ID depends on what IDs are already in use. Option (a) is not a valid SCSI configuration requirement.
In a modem using dibit phase encoding has bit rate
A)
Same as the baud rate
B)
Higher than its baud rate
C)
Lower than its baud rate
D)
Independent of its baud rate
In dibit phase encoding, each signal element represents 2 bits (a dibit). Therefore, the bit rate is 2 times the baud rate. Since bit rate = baud rate × bits per signal element, the bit rate is higher than the baud rate. Hence, option (b) is correct. Option (a) would be true only when 1 bit is transmitted per baud, and options (c) and (d) are incorrect.
The terms “red book”, “yellow book”, and “orange book” refer to
A)
SCSI
B)
Ide
C)
Floppy drive technology
D)
CD-ROM standards
The terms "red book", "yellow book", and "orange book" are color-coded standards related to compact discs. The Red Book specifies audio CD standards, the Yellow Book specifies CD-ROM standards, and the Orange Book covers recordable CD formats. Therefore, the correct answer is CD-ROM standards. The other options are unrelated hardware/interface technologies.
The capacitor charging current is
A)
Exponentially growth function
B)
Exponentially decay function
C)
Linear decay function
D)
Linear rise function
In an RC charging circuit, the capacitor voltage rises with time, so the voltage across the resistor decreases. Since charging current i(t) = V/R × e^(-t/RC), it starts maximum at t = 0 and decays exponentially to zero as the capacitor gets fully charged. Therefore, the capacitor charging current is an exponentially decaying function. The linear options are incorrect, and it is not a growth function because the current does not increase during charging.
A scheme in which portions of I/O address space are given to I/O devices, is called
A)
Data mapped
B)
Memory-mapped I/O
C)
Backplane
D)
Both (a) and (b)
In memory-mapped I/O, certain address ranges of the processor’s address space are reserved for I/O devices, so portions of the address space are given to devices. This allows CPU instructions used for memory access to also access I/O registers.
Why others are incorrect:
- (a) Data mapped: not a standard term for this concept.
- (c) Backplane: refers to a hardware interconnection structure, not address mapping.
- (d) Both (a) and (b): only memory-mapped I/O is correct.
In a series resonance circuit, the impedance of the circuit is
A)
Minimum
B)
Maximum
C)
Zero
D)
Infinite
In a series resonance circuit, the inductive reactance and capacitive reactance are equal and cancel each other out. So the circuit impedance becomes purely resistive and takes its minimum value, equal to the resistance only. Hence, the correct answer is Minimum. It is not maximum or infinite; those are not true for series resonance.
Arrange the words given below in a meaningful sequence. 1. Police 2. Punishment 3. Crime 4. Judge 5. Judgement
A)
3, 1, 2, 4, 5
B)
1, 2, 4, 3, 5
C)
5, 4, 3, 2, 1
D)
3, 1, 4, 5, 2
A meaningful sequence follows the usual criminal justice process: first comes a Crime, then the Police investigate/arrest, then the Judge gives the Judgement, and finally Punishment is awarded. So the correct order is 3 → 1 → 4 → 5 → 2. The other options place Punishment or Judgement before the Judge, which is illogical.
Catching the earlier train will give us the ...... to do some shopping.
A)
chance
B)
luck
C)
possibility
D)
occasion
The sentence means that by catching the earlier train, we will have an opportunity to do some shopping. The most suitable word is 'chance'. 'Luck' is not appropriate because shopping is not dependent on fortune here. 'Possibility' is too indirect and awkward in this context. 'Occasion' can mean an event or suitable time, but 'chance' is the natural and correct choice.
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