- Feedback in an amplifier always helps to
A. Control Its output
B. Increase Its gain
C. Decrease its input impedance
D. Stabilize Its gain Ans. A - The internal resistance of a saturated Weston cell is of the order of
A. A few hundred ohms
B. Negligible
C. Infinite
D. Thousand ohms Ans. A - If two or more interrupts occur during execution, the sequence of appearance of interrupt’s Is called
A. Multi-interrupt
B. Nested Interrupt
C. interrupt within interrupt
D. Nested Interrupt and Interrupt within interrupt Ans. D - The condition occurring when two or more devices try to write data to a bus simultaneously is
A. Address decoding
B. Bus contention
C. Bus collisions
D. Address multiplexing Ans. B - 1n memory mapped scheme, the devices are viewed as
A. Distinct I/O devices
B. Memory locations
C. Only Input devices
D. Only output devices Ans. B - The process of refreshing the data In RAM to reduce the possibility of data loss Is known as
A. Data cycle
B. Retain cycle
C. Regain cycle
D. Refresh cycle Ans. D
- The Instruction, MOV AX, 2 OH Is an example of
A. Register addressing mode
B. Direct-addressing mode
C. Immediate addressing mode
D. Based indexed addressing mode Ans. C - The instruction that unconditionally transfer the control of execution to the specified address Is
A. JMP
B. RET
C. CALL
D. IRET Ans. A - Unlike microprocessors, micro controllers make use of batteries because they have
A. High power dissipation
B. Low power consumption
C. Low voltage consumption
D. Low current consumption Ans. B - Ripple factor of a bridge rectifier Is A. 0.5
B. l
C. 2
D. 0.75
Ans. A - Which of the following is NOT a purpose of Disturbance Monitoring?
A. Model validation
B. Disturbance investigation
C. incorrect relay setting ꞏ
D. Assessment of system protection performance Ans. C - Which of the following is not a basic category of measurement?
A. Null
B. Validity
C. Direct
D. Indirect Ans. B - Use of functions is that they can be used to and to make program more understandable
A. Increase code duplication
B. Decrease code duplication
C. Sub Program Ans B
- The large or surge impedance loading of a long transmission line can be increased without adversely affecting its stability by connecting a lumped
A. Inductance in series with the line
B. Inductance in shunt with the line
C. Capacitance in shunt with the line
D. Capacitance in series with the line Ans. D - As compared to oscillators, inverter provides
A. Low voltage output
B. Low frequency output
C. Distortion less output
D. Noise less output Ans. B - A can be used to make automated potentiometer in comparison measurements.
A. Analog to digital converter
B. Digital to analog converter
C. Electrometer
D. Precision meter Ans. B - Depletion region of diode contains
A. No mobile charge carriers
B. A small number of mobile carriers
C. A large number of mobile carriers
D. The number of mobile carriers depend upon temperature Ans. A - The analog to digital converter provides of input signal.
A. Representation
B. Quantization
C. Maximum value
D. All Information Ans. B - A higher directivity is specified by
A. High gain low bandwidth
B. High gain high bandwidth
C. Low gain low bandwidth
D. Low gain high bandwidth Ans. A - GSM uses
A. FDMA
B. TDMA
C. Both
D. None of above Ans. C
- Advanced mobile phone systems ( AMPS)
A. FDMA
B. TDMA
C. Both
D. None Ans. B - Which Modulation has higher data rates? AM
FM QAM QPSK
Ans. C - Fly back converter is used for
A. AC-AC
B. AC-DC
C. DC-DC
D. DC-AC
E. Both B&C Ans. E - Large phase mercury arc rectifier Is used as
A. Inverter
B. Rectifier
C. Both
D. None Ans. B - In a transformer it is difficult to measure the efficiency by output-Input measurement methods because
A. The output Is sinusoidal and hence cannot be determined
B. Losses are abnormally high
C. Efficiency of transformer Is usually high and hence extremely accurate measurements will be necessary
D. Outputs out of phase with respect to input Ans. C - Series capacitor compensation is used to
A. Increase the series reactance between load and supply
B. Reduce the series reactance between load and
C. Supply the reactive power
D. Increase voltage dip on load Ans. B - Shunt reactors are needed
A. To boost receiving end voltage under light loads
B. To boost receiving end voltage under heavy loads
C. To bring down receiving end voltage at light loads
D. To bring down receiving end voltage under heavy loads Ans. C
- In a transfer function gain k=0 root locus roots are
A. Break In point
B. Open loop poles
C. Break away points
D. Open loop zeros Ans. B - TDMA uses
A. Phase modulation
B. Frequency modulation
C. Amplitude modulation
D. All of above Ans. A - Output occurring due to only Input with zero Initial conditions is called
A. Zero state
B. Zero Input
C. Absolute state
D. Real state Ans. A - The maximum loads attached to a device called
A. Fan In
B. Fan out
C. Phase In
D. Phase out Ans. B - Link layer design is also called
A. Transport layer
B. Access layer
C. Data layer
D. Protocol design layer
E. Network layer Ans. C - TCP/IP address is how many bits
A. 16 bits
B. 32 bits
C. 64 bits
D. 128 bits Ans. B - If two 16-bit numbers are multiplied then the result Is
A. Two bytes
B. Four bytes
C. Six bytes
D. Eight bytes Ans. B
- Differential amplifier uses which coupling Transformer coupling
RC coupling Direct coupling None of above Ans. C - The main advantage of autotransformer over a two winding transformer is that
A. No cooling is required
B. Hysteresis losses are minimized
C. Eddy current losses are minimized
D. Only one winding is used as a result there is substantial’ saving in material Ans. D - In a line to ground fault on a system, the fault current is 1500 A, The-zero sequence current is A. 1500A
B. 0A
C. 750 A
D. 500A Ans. D - The torque of an Induction motor is
A. Directly proportional to slip
B. Inversely proportional to slip
C. Proportional to the square of slip
D. Directly proportional to current Ans. A - In which. form, waves reach at the antenna
A. Modulated digital
B. Modulated analog
C. Aligned waves
D. All of above Ans. D - Why are pole tips in DC machine chamfered?
A. To improve commutation characteristics
B. To reduce armature reaction effect Ans. B - The phase difference between the primary and secondary voltage of a transformer
A. 0
B. 90
C. 180
D. Between 30 and 60
Ans. C
- Why is it important to maintain an Impedance match from the source to the load when sending signals?
A. To reduce external noise
B. to keep the line balanced
C. To reduce reflected energy
D. To reduce attenuation Ans. C - Power input to a transformer at no load and rated voltage consists of
A. Eddy current loss
B. Hysteresis loss
C. Copper loss
D. Core loss Ans. D - In a transformer, no load current
A. leads the applied voltage, by 90
B. Lags the applied voltage by 90
C. lags the applied voltage by somewhat less than 90
D. Leads the applied voltage by somewhat less than 90 Ans. C - Number of cycles generated in 8 pole alternator in one revolution
A. 2
B. 4
C. 8
D. 16 Ans. B - What limits design of long transmission line?
A. Thermal considerations
B. Conductor area
C. Both A & B
D. None of above Ans. B - Which of following terms are related to PWM?
A. NRZ
B. RZ
C. Both
D. None of the above Ans. C - What Is the main task of power electronics?
A. AC-DC conversion
B. AC-AC conversion
C. DC-AC conversion
D. A & C Ans. A
- The bit used for error detection and retransmission is named as
A. Parity bit
B. First bit
C. Low bit
D. High bit Ans. A - In a DC machine, the angle between the stator and rotor fields is
A. 0
B. 90
C. 180
D. 270
Ans. B - Torque of an indicating meter depends upon
A. Spring
B. Gravity
C. Both
D. None Ans. C - If gauge of copper is increased in impedance matching transformer what will happen
A. Resistance will Increase
B. Resistance will decrease
C. Resistance remains the same
D. None of the above Ans. A - A 440V, 100W bulb on 220V will behave like a
A. 25W
B. 50W
C. 75W
D. None Ans. A - Doped semiconductor material has temperature coefficient of
A. Positive
B. Negative
C. Neither positive nor negative
D. Either positive or ‘negative Ans. A - Laplace transform is used for solving
A. Complex equations
B. Differential equations
C. Linear equation
D. Quadratic equations
Ans. B
- If 1 Hz frequency is applied to the field of dc machine armature EMF will be
A. 1 Hz sinusoidal
B. DC
C. 1 Hz square wave
D. None of above Ans. A - Heating value is measured by
A. Hygrometer
B. Barometer
C. Altimeter
D. Bomb calorimeter Ans. D - Which of the following is not running cost of the thermal power plant?
A. Equipment
B. Fuel
C. Workers
D. Maintenance Ans. A - Calorific value Is usually given by unit of energy divided by
A. Mass (usually)
B. Volume
C. Weight
D. Density Ans. A - Efficiency of thermal power plant is measured by subtracting efficiency of turbine from
A. Boiler
B. Condenser
C. Compressor
D. None of these Ans. A - The time of power plant which is obtained by dividing average time by total time Is called
A. Plant operating factor
B. Demand factor
C. Plant capacity factor
D. Diversity Factor Ans. A - Total number of stages in gas turbine power plant
A. Four
B. Two
C. Six
D. None
Ans. A
- The method in which customer pays some fixed cost along with Peak demand cost and total electricity usage cost
A. Two-part tariff
B. Three-part tariff
C. Commercial tariff
D. None of the above Ans. B - Which hydel plant has lowest production capacity?
A. Rasul Barrage
B. Dargai Hydro Plant
C. Gomal Zam Dam
D. Duber Khawar Hydro Ans. C - Calorific value of which fuel is highest
A. Anthracite
B. Hydrogen
C. Coal
D. Natural gas Ans. B - Which winding of transformer has less cross-sectional area?
A. Primary winding
B. Secondary Winding
C. Low voltage winding
D. High voltage winding Ans. D - A helical antenna is used in satellite tracking because of its
A. Circular polarization
B. Maneuverability
C. Broad bandwidth
D. Good front to back ratio Ans. A - A heterodyne frequency changer is called a
A. Modulator
B. Mixer
C. Demodulator
D. frequency translator Ans. B - The process in which the signal is first compressed before modulation and expanded after demodulation so as to allow the use of a uniformly quantizing rate is known as
A. Pre emphasis
B. De-emphasis
C. Quantization
D. Companding Ans. D
- Frequency shift keying Is used mostly In
A. Radio transmission
B. Telegraphy
C. Telephone
D. Satellite communication Ans. B - LVOT (linear variable differential transformer) is a device
A. Electrodynamic
B. Electromechanical
C. Electromagnetic
D. Electrostatic Ans. B - The autocorrelation function is
A. An odd function
B. An even function
C. An exponential function in to
D. None Ans. B - Probability density function of thermal noise is
A. Binomial
B. Poisson
C. Gaussian
D. None of these Ans. C - If 360 coulomb charge is stored for a time period of 30 minutes. What will be the current?
A. 200mA
B. 20A
C. 2A
D. 20mA Ans. A - The potential difference between two similar charges is
A. Same
B. Infinite
C. Nil
D. None of above Ans. C - Mass, in Force-voltage analogy, is analogous.to
A. Charge
B. Current
C. Inductance
D. Resistance
Ans. C
- Top loading Is sometimes used with an antenna in order to
A. Decrease its input impedance
B. Increase its height
C. Increase its effective height Ans C - A rhombic antenna is a
A. Resonant
B. Non resonant
C. Either of the above Ans, B - The carrier of a 100% modulated AM wave Is suppressed, the % power saving Is
A. 100%
B. 83%
C. 50%
D. 66.66%
Ans D - Burning material such as wood, paper and textile constitute which type of fire
A. Class A
B. Class B
C. Class C
D. Class D Ans. A - The radiation pattern of a parabolic-antenna ꞏ1s
A. Omni directional
B. A figure of eight
C. Highly directional
D. None Ans. C - Execution of program Instruction in computer takes place in
A. RAM
B. ROM
C. Hard disk
D. Mother board Ans A - The breakdown voltage in gases depends on
A. Distance between electrodes
B. Relative air density
C. Humidity
D. All of these Ans D - Turbo alternators are characterized by
A. Short diameter and great axial length
B. Large diameters and great axial lengths Ans. A - An ammeter is convertible to a voltmeter by
A. Changing the scale
B. Putting a large resistance in parallel with the actual measuring part of the Instrument
C. Putting a large resistance in series with the actual measuring part of the Instrument Ans. C - Transformers are designed to have leakage Induction.
A. Zero
B. Low
C. High
D. Medium Ans. B - The path of the magnetic flux in transformer should have
A. Low reluctance
B. Low resistance
C. High reluctance
D. High resistance Ans. A - For transmitting power on a 20-25-km line which voltage should be used
A. 5kV
B. 11KV
C. 33KV
D. 66kV Ans. B - Due to low budget the weight of the conductor is to be reduced by 25 %. using the same conductor material, as a power engineer what will you do
A. Reduce the voltage level
B. Double the voltage level
C. Reduce the frequency level
D. None of the above Ans. B - In a current is induced with mechanical motion of the conductor
A. Transformer
B. Generator
C. Thyristor
D. None of the above Ans. B - 1000 million tons coal is required to generate 1000 MW for a year, for uranium this fuel amount to
A. 10-15
B. 20-25
C. 30-35
D. 40-45
Ans. C - E= N dv/ dt is called
A. Lenz’s law
B. Faraday’s law
C. Gauss’s Law
D. Amperes Law Ans. B - In real power system constant used a + j b, j is called
A. √1
B. √—1
Ans. B
- Capacity factor =0.628, maximum demand is 325 MW, plant capacity is 350 MW, calculate load factor, Average load= 250 MW
A. 0.8
B. 0.67
Ans. BActual answer is 0.76 (NTS mistakenly writes answer as 0.67) - For transmission lines the standing wave ratio is the ratio of
A. Maximum voltage to minimum voltage
B. Maximum current to minimum voltage
C. Peak voltage to RMS voltage
D. Maximum reactance to minimum reactance Ans. A - In order to improve the steady state stability of overhead transmission lines, which of the following methods can be adopted
A. Reducing impedance between the stations
B. Adopting quick response excitation
C. Using series capacitors to make X = √3R
D. Any of the above Ans. D - Difference between AC and DC generator?
A. The AC generators carry slip rings while DC require commutator
B. The DC generators carry slip rings while AC generators require a commutator
C. Both AC and DC generators carry slip rings
D. Both AC and DC generators require a commutator Ans. A - In shunt generator, the shunt winding is parallel with the armature its advantage is
A. Single source is used to excite both
B. Eliminates need for external excitation
C. Both
D. None of above Ans. B
- The turbines of run of river hydel power plant (low head turbines) deal with which kind of water
A. Less volume and low pressure
B. Less volume and high pressure
C. High volume and low pressure
D. High volume and high pressure Ans. C - If a large load is disconnected suddenly from an alternator or a power system, then
A. Turbine speed increases and frequency also increases
B. Turbine speed decreases and frequency also decreases
C. Turbine speed increases and frequency decrease
D. Turbine speed decreases but frequency increases Ans. A
Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 5(401-500)