INDUSTRIAL AND POWER ELECTRONICS 2

1. The function of bleeder resistance in filter circuits is that
a) to maintain minimum current necessary for optimum inductor filter operation.
b) to work as voltage divider in order to provide variable output from the supply.
c) to provide discharge path to capacitors so that output becomes zero when the circuit has been de-energized
d) All of these
ans. d

2. In a 3-phase half wave rectifier, each diode conducts for a duration of
a) 180 degrees
b) 30 degrees
c) 60 degrees
d) 45 degrees
ans. c

3. Ripple frequency of a 6-phase half-wave rectifier for 230 V, 50 Hz input will be
a) 150 Hz
b) 50 Hz
c) 300 Hz
d) 100 Hz
ans. c

4. As the number of phases in a multi-phase rectifier are increased the output will
a) increase
b) become more smooth
c) decrease
d) the diodes will require high peak inverse voltage
ans. b

5. For a rectifier output of 150 kW at 500 V , an average current rating of 50 A for each diode is sufficient in
a) 3-phase full wave rectifier
b) 6-phase half wave rectifier
c) 3-phase half waver rectifier
d) none of these
ans. b

6. The effect of DC saturation in a rectifier transformer is
a) to decrease the output
b) to increase the output
c) to decrease the ac components of the output
d) none of these
ans. a

7. In a 3-phase half wave rectifier, the output voltage is equal to
a) the most positive in phase voltage at any instant
b) the difference of most positive and most negative input phases at any instant
c) the average value of the three phases.
d) the difference of the two positive phase voltages
ans. a

8. In a 3-phase half wave rectifier, if the input phase voltage is 200 V, the PIV required for each diode will be
a) 400 V
b) 346 V
c) 370 V
d) 200 V
ans. c

9. The rectifier , which requires minimum amount of filtering is
a) half wave rectifier
b) full wave rectifier
c) voltage doubler circuit
d) SCR half-wave rectifier
ans. d

10. A capacitor of 100 µF is charged to 10 V through a resistance of 10 K . It will be fully charged in
a) 5 sec
b) 0.1 sec
c) 1 sec
d) 0.5 sec
ans. a

Safety AND Security of Women

Safety AND Security of Women.

ENGINEERING MATERIALS

1. Instruments used for separation of isotopes are known as
a) mass spectrographs
b) atomic spectrographs
c) molecular spectrographs
d) All of the above
ans. a

2. Unit of plank’s constant is
a) erg sec
b) joules
c) joules/sec
d) erg/sec
ans. d

3. A set of four quantum numbers describe
a) energy level only
b) energy state only
c) energy level and energy state
d) All of these
ans. b

4. The capacity of a single orbital is
a) 2
b) 6
c) 10
d) 18
ans. a

5. The atomic number of the element whose outermost electron fills the 3s shell is
a) 8
b) 12
c) 18
d) none of these
ans. b

6. In the modern Periodic Table, elements are arranged in order of increasing
a) atomic weight
b) atomic number
c) molecular weight
d) none of these
ans. b

7. Avagadro’s number is the number of
a) atoms in one gram mole
b) molecules in one gram mole
c) both A and B are correct
d) all of these
ans. b

8. Ionic bonding in solids depends primiarily on
a) electrical dipoles
b) sharing electrons
c) transfer of electrons
d) all of these
ans. c

9. The nature of atomic bond found in diamond is
a) ionic
b) covalent
c) metallic
d) all of these
ans. b

10. Which of the following material does not have covalent bonds?
a) metal
b) organic polymers
c) silicon
d) all of these
ans. a

NITYA

FUNDAMENTALS OF ELECTRICITY

1. Which particles act as a current carrier in a metallic conductor?
a) only electrons
b) only ions
c) electrons and defect elections
d) electrons and ions
ans. a

2. If an atom looses one or more electrons it becomes
a) electrically neutral
b) electrically positive
c) electrically negative
d) a neutral ion
ans. b

3. What other effect of the electric current is also present in the fluorescent lamp and causes losses in the efficiency of the lamp?
a) The chemical effect
b) The magnetic effect
c) The heating effect
d) The chemical and the magnetic effect
ans. b

4. What is the unit of charge ?
a) Volt-ampere VA
b) Henry H
c) Farad F
d) coulomb C
ans. d

5. Static electricity is produced by
a) chemical reaction
b) friction
c) induction
d) both friction and induction
ans. b

6. The sure test of electrification is
a) induction
b) friction
c) repulsion
d) attraction
ans. c

7. The space surrounding a charge body , within which the influence of its charge extends is called
a) coulombs
b) electric field
c) electric intensity
d) lines of force
ans. b

8. Paper condenser is a type of
a) variable condenser
b) electrolytic condenser
c) fixed condenser
d) none of these
ans. c

9. Mica or ceramic condenser is a type of

a) variable condenser
b) electrolytic condenser
c) fixed condenser
d) none of these

ans. c

10. With the rise of temperature, dielectric strength of the material 

a) increases

b) remains constant

c) decreases

d) becomes zero

ans. c

ELECTROMAGNETICS

1. The force tending to move the electricity is called
a) current
b) resistance
c) emf
d) potential difference
ans. c

2. The ratio of voltage and current in a closed circuit
a) varies
b) remains constant
c) increases
d) decreases
ans. b

3. The meter which measures current is known as
a) voltmeter
b) avometer
c) ohm meter
d) ammeter
ans. d

4. The meter which measures voltage is known as
a) avo meter
b) ampere meter
c) voltmeter
d) multimeter
ans. c

5. The meter which measures voltage is known as
a) ohm meter
b) multimeter
c) voltmeter
d) ohm meter
ans. d

6. The unit of resistance is
a) ohm
b) volt
c) ampere
d) milli-volt
ans. a

7. For long transmission lines, voltage is measued in
a) volts
b) micro-volts
c) kilo-volts
d) milli-volts
ans. c

8. With the increase in length of conductor, the value of resistance
a) decreases
b) increases
c) remains same
d) none of these
ans. b

9. With the increase in cross-sectional area of the conductor, the value of resistance
a) increases
b) remains same
c) decreases
d) none of these
ans. c

10. Specific resistance of a conductor depends upon
a) composition of the conductor
b) length of the conductor
c) area of cross section of the conductor
d) resistance of the conductor
ans. a

MECHANICAL SYSTEMS

1. The working voltage of a capacitor to which AC of pulsating DC is applied should be 

a) the same as or greater than the applied voltage

b) at least 50% greater than the applied voltage

c) 1.41 times the applied voltage

d) 0.707 times applied voltage

ans. b

2. A circuit contains 10 ohms of resistance, 20 ohms of inductive reactance, and 30 ohms of capacitive reactance. The circuit is

a) inductive

b) in resonance

c) resistive

d) capacitive

ans. d

3. The opposition offered by a coil to the flow of alternating current is known as

a) conductivity 

b) impedance

c) reluctance 

d) inductive reactance

ans. d

4. An increase in the inductive reactance of a circuit will be due to increase in 

a) inductance and frequency

b) capacitance and voltage

c) resistance and voltage

d) resistance and capacitive reactance

ans. a

5. The resistive force in a DC electrical circuit is measured in ohms and referred to as

a) resistance

b) capacitance

c) reactance 

d) inductance

ans. a

6. When the capacitive reactance in an AC electrical circuit is equal to the inductive reactance, the circuit is

a) in correct voltage phase angle

b) in correct current phase angle

c) out of phase

d) resonant

ans. d

7. In an alternating current circuit, the effective voltage

a) is equal to the maximum instantaneous voltage

b) is greater than the maximum instantaneous voltage

c) may be greater than or less than the maximum instantaneous voltage

d) is less than the maximum instantaneous voltage

ans. d

8. The amount of electricity a capacitor can store is directly proportional to 

a) the distance between the plates and inversely proportional to the plate area.

b) the plate area and is not affected by the distance between the plates

c) the plate area and inversely proportional to the distance between the plates

d) the distance between the plates and is not affected by the plate area

ans. c

9. A transformer step-up ratio of 5 to 1 has a primary voltage of 24 V and a secondary amperage of 0.20 A. The primary amperage will be

a) 1 A

b) 4.8 A

c) 0.40 A

d) cannot be determined from the information given

ans. a

10. The phase relationship between the current and voltage in an inductive circuit is

a) The current lags the voltage by 0 degrees

a) The current lags the voltage by 90 degrees

a) The current leads the voltage by 90 degrees

a) The current leads the voltage by 0 degrees

ans. a

COMMUNICATION SYSTEMS

1. Which of the following statements is not true for modulation?
a) it allows the use of practicable antennas.
b) It ensures transmission over long distances.
c) It reduces the bandwidth.
d) It separates different transmissions.
ans. c

2. Which of the following is not an advantage of SSB over double-side band full carrier?
a) Noise in the signal is less.
b) More channel space is available
c) Less power is required for the same signal strength.
d) None of these
ans. d

3. A modulator is a system to
a) Separate two frequencies
b) Impress the information on to a radio frequency carrier .
c) extract information form the carrier.
d) amplify the audio frequency signal.
ans. b

4. In a demodulator of a typical superhet broadcast receiver (medium and short-wave), the frequency of the input will be approximately
a) 10 MHz
b) 10 KHz
c) 500 KHz
d) 1000 Hz
ans. c

5. In AM transmission, the frequency which is not transmitted is
a) Upper side frequency
b) lower side frequency
c) audio frequency
d) carrier frequency
ans. c

6. The AM broadcast band is given by
a) 10 KHz to 30 KHz
b) 500 KHz to 1500 KHz
c) 3 to 30 MHz
d) 30 to 300 MHz
ans. b

7. In an AM wave with 100% modulation , the carrier is suppressed. The percentage of power saving will be
a) 100%
b) 50 %
c) 25 %
d) 66.7%
ans. d

8. A 400-W carrier AM modulated to a depth of  75%. The total power of the modulated wave would be
a) 210 W
b) 512 W
c) 450 W
d) 620 W
ans. b

9. The antenna current of an AM transmitter is 8 A when only carrier is sent, but is increases to 8.93 A when the carrier is modulated. The modulation of the wave is
a) 43 %
b) 57 %
c) 70.7 %
d) 100 %
ans. c

10. In high-power AM transmission, modulation is done at
a) buffer stage
b) RF power stage
c) oscillator stage
d) IF stage
ans. b

SEMICONDUCTORS DEVICES

1. Electronics is the branch of engineering which deals with flow of electrons through
a) semiconductor
b) gas
c) vaccum
d) all of these
ans. d

2. The liberation of electrons from the surfaces of a substance is called
a) bombardment of electrons
b) electronic emission
c) movement of free electrons
d) ions emission
ans. b

3. The metal from which the electrons are emitted is called
a) an emitter
b) a cathode
c) an emitter or a cathode
d) none of these
ans. c

4. An emitter is generally called
a) anode
b) cathode
c) grid
d) drain
ans. b

5. Oxide-coated cathode is used in
a) low power tubes
b) medium power tubes
c) high power tubes
d) medium and high power tubes
ans. a

6. The emitter must have the following characteristics:
a) high melting point
b) low value of work function
c) immunity to reaction from residual gasses and water vapours
d) All of these
ans. d

7. In an indirectly heated cathodes
a) filament is not used
b) filament heater is used
c) filament heater may or may not be used
d) high voltage is used
ans. b

8. An electron tube can only operate when
a) anode is negative with respect to cathode
b) anode is positive with respect to cathode
c) anode must be at zero potential with respect to cathode
d) anode must be earthed
ans. b

9. The work function of metal is generally expressed is
a) joules
b) volts
c) electrons
d) electron volt
ans. d

10. The process of conversion ac into dc is called
a) amplification
b) modulation
c) rectification
d) factorization
ans. c

INDUSTRIAL AND POWER ELECTRONICS

1. The major advantage of a bridge rectifier is that
a) no centre-tap transformer is required
b) the required peak inverse voltage of each diode is double of that for a fullwave rectifier
c) peak inverse voltage of each diode is half of that for a full-wave rectifier
d) the output is more smooth
ans. c

2. A bridge rectifier provides 50 mA current at 150V : The transformer voltage specification is
a) 220 V:167 V
b) 120 V:150 V
c) 220 V:236 V
d) 120 V:110 V
ans. a

3. A bridge rectifier provides 50 mA current at 150V. The average current and PIV of each diode, respectively are
a) 79 mA, 167 V
b) 25 mA, 236 V
c) 79 mA, 236 V
d) 25 mA, 120 V
ans. b

4. Which of the following circuits cannot be operated directly from the mains?
a) Half-wave rectifier
b) Centre-tap full wave-rectifier
c) Bridge rectifier
d) voltage doubler
ans. b

5. For a filter , no load output voltage is 300 V and full-load output voltage is 280 V . The voltage regulation of the circuit is
a)  9.6%
b) 7.1%
c)  6.7%
d) 4.2%
ans. a

6. A typical value of filter capacitor for 50 Hz input is
a) 1000 microF
b) 50 microF
c) 10 microF
d) 100 pF
ans. b

7. A typical value of induction filter for 50Hz input is
a) 10 H
b) 100 mH
c) 10 mH
d) 100 microH
ans. a

8. If the ripple factor of the output wave of a rectifier is low, it means that
a) output voltage will have less ripple
b) output voltage will be low
c) filter circuits may not be required
d) none of these
ans. a

9. In a rectifier circuit, the load connected is of low value. For proper filter operation, it is required that
a) a capacitor is to be included in the circuit
b) a bleeder resistance is to be placed in the circuit
c) an inductor filter is to be included in the circuit
d) all of the above
ans. c

10. The limitation of the voltage multiplying circuit is that
a) the output has high ripple content
b) high output voltage is difficult to obtain
c) high output current is difficult to obtain
d) the size of the capacitors become very large
ans. c

CONTROL SYSTEMS

1. Which statement is not correct for open loop control system?
a) Simple construction and ease of maintenance
b) less expensive
c) disturbances cause errors
d) To maintain the required quality in the output, recalibration is not required
ans. d

2. In a feedback amplifier, the bandwidth
a) decreases by the same amount as the gain decrease
b) increases by the same amount as the gain decrease
c) decreases by the same amount as the gain increases
d) remains unaffected
ans. b

3. Introduction of negative feedback in a system does not lead to reduction in
a) bandwidth
b) distortion
c) instability
d) overall gain
ans. a

4. The sensitivity of a closed-loop system to gain changes and load disturbances depends upon
a) forward gain
b) loop gain
c) frequency
d) all of these
ans. d

5. In a feedback system the transient response
a) decays at a constant rate
b) gets magnified
c) decays slowly
d) decays more quickly
ans. d

6. The frequency and the domain are related through
a) laplace transform
b) fourier integral
c) laplace transform or fourier integral
d) laplace transform and fourier integral
ans. d

7. Error constants of system are a measure of
a) steady state response
b) transient-state response
c) relative stability
d) steady-state as well as transient response
ans. a

8. Static error coefficients are used as a measure of the effectiveness of closed-loop systems for specified
a) position input signal
b) velocity input signal
c) acceleration input signal
d) all of these
ans. d

9. Velocity error constant of a system is measured when the input to the system is
a) unit step function
b) unit ramp function
c) unit impulse function
d) unit parabolic function
ans. b

10. Bandwidth is used as means of specifying performance of a control system related to
a) relative stability of the system
b) the speed of response
c) the constant gain
d) all of these
ans. b

UTILIZATION OF ELECTRICAL ENERGY

1. Which of the following is preferred for automatic drives?

a) Synchronous motors

b) Squirrel cage induction motor

c) Ward-Leonard Controlled dc motor

d) any of these

ans. c

2. Which type of drive can be used for hoisting machinery?

a) Slip ring induction motor

b) Ward Leonard controlled dc shunt motor

c) DC compound motor

d) any of these

ans. c

3. The motor normally used for crane is 

a) Slip- ring induction motor 

b) Ward Leonard Controlled DC shunt motor

c) Synchronous motor

d) DC differentially compound motor

ans. a

4. A wound rotor induction motor is preferred over squirrel cage induction motor when the major consideration involved is 

a) high starting torque

b) low starting current

c) speed control over limited range

d) all of these

ans. d

5. When smooth and precise speed control over a wide range is desired, the motor preferred is 

a) synchronous motor

b) squirrel cage induction motor

c) wound rotor induction motor

d) dc motor

ans. d

6. when quick speed reversal is a consideration the motor preferred as

a) synchronous motor

b) squirrel cage induction motor

c) wound rotor induction motor

d) dc motor

ans. d

7. DC supply can be obtained from AC supply by the use of

a) motor generator set

b) mercury arc rectifier

c) silicon diodes

d) any of these

ans. d

8. The selection of control gear for a particular application is based on the consideration of 

a) duty 

b) starting torque

c) limitations on starting current

d) all of these

ans. d

9. The consideration involved in the selection of the type of electric drive for a particular application depends on 

a) speed control range and its nature

b) starting torque

c) environmental conditions

d) all of these

ans. d

10. As compared to squirrel cage induction motor a wound rotor induction motor is preferred when the major consideration is 

a) high starting torque

b) low windage losses

c) slow speed operation 

d) all of these

ans. a

MEASURING SYSTEMS AND INSTRUMENTATION

1. The meter used for measuring electrical quantities are
a) Tachometer
b) Micrometer
c) Measuring instruments
d) Spherometer
ans. c

2. The meter used for electrical power is called
a) kWh meter
b) Voltmeter
c) Ammeter
d) Wattmeter
ans. d

3. The meter used for measuring potential difference of a circuit is called
a) voltmeter
b) ammeter
c) energy meter
d) ohm meter
ans. a

4. The meter used for measuring current of an electrical circuit is called
a) voltmeter
b) ammeter
c) potentiometer
d) multimeter
ans. b

5. The meter used for measuring electrical energy of consumer is called
a) wattmeter
b) ampere hour meter
c) kWh meter
d) avometer
ans. c

6. The essential requirement of measuring instrument is
a) deflecting torque
b) controlling torque
c) damping torque
d) all the above
ans. d

7. The deflecting torque can be produced by
a) gravity control
b) spring control
c) air friction
d) magnetically
ans. d

8. The controlling torque can be produced
a) electrostatically
b) thermally
c) by using hair spring
d) by fluid friction
ans. c

9. The damping torque can be produced by
a) eddy currents
b) gravity control
c) electrostatically
d) thermally
ans. a

10. Electrostatic effect for producing deflecting torque is used in
a) ammeters
b) voltmeters
c) wattmeters
d) energy meters
ans. b

EMBEDDED SYSTEMS

THE EMBEDDED DESIGN LIFE CYCLE

The design of an embedded system implies that both software and hardware are being designed in parallel.
There are 7 phases in designing an embedded system

• Product specification
• Partitioning of the design into its software and hardware components
• Iteration and refinement of the partitioning 
• Independent hardware and software design tasks
• Integration of the hardware and software components
• Product testing and release
• On-going maintenance and upgrading

The embedded design process is not simple considerable amount of iteration and optimization occurs within phases and between phases. Defects found in later stages cause loss. 

POWER SYSTEMS

1. Which of the following plants will have the highest capital cost
a) Nuclear power plant
b) Diesel power plant
c) Thermal power plant
d) None of these
ans. a

2. Which of the following plants have the minimum running cost
a) Nuclear power plant
b) Diesel plant
c) Thermal power plant
d) Hydro power plant
ans. d

3. In a steam power plant water is used for cooling purposes in
a) Condenser
b) turbine only
c) boiler tubes
d) boiler tubes and turbine both
ans. a

4. Which of the following power stations is mainly used to cover peak loads on the system?
a) Brown coal power station
b) Pit coal power station
c) Nuclear power station
d) Pump storage water power station
ans. d

5. What is the advantage of hydro-electric power stations over thermal power stations?
a) The initial cost of hydro-electric power stations is low
b) Their operating cost is low
c) Hydro-electric power stations can supply the same power throughout the year
d) Hydro-electric power stations can be constructed where electric energy is required
ans. b

6. Water is supplied to a boiler
a) at 140 kg/cm²
b) at atmospheric pressure
c) at slightly more than atmospheric pressure
d) at more than the steam pressure in the boiler
ans. d

7. The pH value of water used for boiler is 
a) unity
b) 7 
c) 10
d) slightly more than seven
ans. d

8. In one year there are about 
a) 365 full tidal cycles
b) 730 full tidal cycles
c) 705 full tidal cycles
d) none of the above
ans. c

9. The oldest geothermal power plant is in 
a) France
b) Germany
c) Italy 
d) USA
ans. c

10. The MHD system generates
a) a.c only 
b) d.c only 
c) a.c and d.c both
d) either a.c or d.c 
ans. c