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OBJECTIVE QUESTIONS
Course Name
: Electrical and Electronics Engineering
Course Code
: A30203
Class
: II B. Tech I Semester
Branch
: Mechanical Engineering
Year
: 2015 – 2016
Course Faculty
: Mr.M Sreenivasa Reddy, Associate Professor
UNIT-1:
1. Which of the following are the units of the Resistance?
(A) Amperes (B) Volts (C) Watts (D)Ohms
2. Kirchhoff’s Voltage Law is Based on Law of Conservation of
(A) Energy (B) charge (C) Voltage (D) None
3. What are the Factors of effecting on Resistance?
(A) Temperature (B) Length of conductor (C) A&B
(D) Voltage
4. Which of the following is an Active Elements?
(A) Inductance (B) Capacitance (C) Voltage source (D) Resistance
5. Which of the following is Passive Elements?
(A) Voltage source
(B) Current Source (C) Power (D) Resistance
6. Inductance in a Circuit
(A) Prevents the Current from changing
(C)Causes power loss
(B) delays the change in Current
(D) causes the Voltage
7. In Parallel Circuit all components must
(A) Have same potential difference a cross them
(C)Carry equal currents
(D) carry same currents
(B) have same value
8. Delta – Star Transformation if equal resistances are given
(A) 3times Increases (B) 3 times reduces (C) same value (D) None
9. Star – Delta Transformation if equal resistances are given its value is
(A) 3times Increases
(B) 3 times reduces
(C) same value (D) None
10. Voltage Division rule is applied for which of the following
(A) Series Circuits (B) Parallel Circuits
(C) both A&B (D) None
11. Kirchhoff’s Current Law is based on Law of Conservation of
(A) Energy (B) charge
(C) Voltage (D) None
12. Current Division rule is applied for which of the following
(A) Series Circuits (B) Parallel Circuits
(C) both A&B (D) None
13. Physical conditions being unchanged In a conductor the flow of current is directly proportional to
(A) Voltage
(B) Current (C) Power (D) None
14. Positive Temperature co-efficient of conductor
(A) R increases, T decreases
(C) R&T are Constant
(B) R increases, T increases
(D) R decreases T decreases
15. The difference in the potentials of two charged bodies is called
(A) Current (B) potential difference (C) work done (D) None
16. which of the following is an acceptable classification of measuring instruments?
a. absolute
b.digital
c. secondary
d.all of these
17. which of the following is an absolute measuring instrument?
a. moving coil
b.tangent galvanometer
c. permanent magnet
d. moving iron
18.which of the following measuring measuring instruments are not categorized as secondary instruments?
a. absolute
c. digital
b.analog
d.all of these
19.which of the following can be categorized as ammeter and voltmeter?
a. hot wire type
b. moving iron type
c. moving coil dynamometer type
d. all of these
20. which of the following can be used for measuring alternating quantities only?
a.moving coil dynamometer type
b. induction typeProportional to Cosθ
c. moving iron type
d.all of these
21.which of the following cannot be used to measure both alternating and direct quantities?
a. moving coil permanent magnet type
c. moving iron type
b.moving coil dynamometer type
d. hot wire type
22. which of the following is not an advantage of movin coil instruments?
a. uniform scale
b. high sensitivity
c. immune to stray magnetic fields d.none of these
23.which of the following is an advantage of moving coil dynamometer instruments?
a. high cost
b.low sensitivity
c. measure both alternating and direct quantities d.none of these
24.which of the following applies to a wattmeter?
a. it has a voltage coil
b.it has current coil
c. the voltage coil has a high resistance
d. all of these
25.wattmeters are available with
a. single current and voltage ratings
b.multiple current rating and single voltage rating
c. single current rating and multiple voltage rating
d.multiple current and voltage ratings
UNIT-2
1. Mechanical Energy Converted to Electrical energy which of the following
(A)Generator (B) Motor (C) Both A&B (D) None
2.The direction of induced e.m.f and hence current in a conductor can be determined by
(A)Lenz’s Law (B) Fleming’s Right hand rule
(C) Both A&B (D) Fleming’s Left hand rule
3.In DC Machine which Induced e.m.f is suitable
(A)Statically induced e.m.f (B) dynamically induced e.m.f (C) there is no e.m.f (D) None
4. The function of the commutator
(A)Ac to dc
(B) dc to ac
(C) both A&B (D) None
5. Brushs are made up of
(A)Carbon (B) Silicon (C) copper (D) Mild steel
6. Armature Reaction is related to
(A)Main flux &Armature flux
(B) only Main flux
(C) only Armature flux
None
7. Which is suitable for Electric Traction?
(A)Series Motor (B) Shunt Motor (C) Compound Motor
(D) Dc Generator
8. Which of the following are Iron Losses?
(A)Copper losses
(B) Mechanical losses
(C) friction loss
(D) Eddy current losses
9. The Basic Principle in dc generator is
(A)Electro Magnetic Induction (B) Flemings Left hand rule (C) Law of conservation Energy
10. DC Motors in Starters are used to
(A)To limit starting current (B) to start the motor
(C) to increase starting current
11. Swinburne’s test conduct on DC Shunt Machine is
(A) No load
(B) Full load
(C) Both A&B
(D) None
(D) to increase line voltage
12. Armature windings are made up on
(A)Copper
(B) Mild wire
(C) Aluminum
(D) None
13. Which of the following is unit of Torque is
(A)Newton-meter
(B) watts
(C) Length
(D) None
14.the starting resistance of a D.C. motor is generally
(A)Low
(B) around 500 ohm
(C) 100 ohm (D) infinitely large
15. Small DC motors up to 5 H.P. Usually
(A) 2 poles (B) 4poles
(C) 6poles
(D) 8poles
UNIT-3
1). Induced e.m.f in a coil is directly proportional to
(a) Rate of change of flux linkage
(b) Rate of change of charge
(c) Depends on the material used(d) Rate of change of current
2). The transformer rating is
(a) KW (b) KVA
(c) KV
(d) WATT
3). The transformer transforms
(a) Frequency
(b) Voltage
(c) Current
(d) Voltage & Current
4). The main purpose of using Core in transformer is to
(a) Decrease Iron losses
(b) Prevent Eddy current losses
(c) Eliminate Magnetic hysteresis
(d) Decrease Reluctance of the Common magnetic circuit
5). The transformer cores are laminated in order to
(a) Simplify its constructions
(c) Reduce cost
(b) Minimize Eddy current losses
(d) Reduce Hysteresis losses
6). The Primary and Secondary induced E.M.Fs E1 & E2 in a Two winding transformer are always
(a) Equal in magnitude
(b) Anti-Phase with each other
(c) In-Phase with each other
(d) Determined by load on transformer Secondary
7). The Step-up transformer increases
(a) Voltage
(b) Current
(c) Power
(d) Frequency
(c) Power
(d) Frequency
8). The Step-down transformer decreases
(a) Voltage
(b) Current
9). The main purpose of performing open circuit test on a transformer is to measure Its
(a) Copper losses
(b) Iron losses
(c) Total losses
(d) Insulation resistance
10). The main purpose of performing short circuit test on a transformer is to measure Its
(a) Copper losses (b) Iron losses
(c) Total losses
(d) Insulation resistance
11). In a transformer the load is connected to
(a) Primary
(b) Secondary
(c) Both (a) & (b)(d) None
12). The efficiency of the transformer depends on
(a) Input power (b) Losses in transformer
(c) Power factor (d) All the above
13). The transformation ratio is
(a) E2/E1
(b) N2/N1
(c) I1/I2 (d) All the above
14). The Cosine angle between the Voltage and Current
(a) Power factor (b) Voltage
(c) Load of the transformer
15) When the transformer is more efficiency
(a) Constant load current (b) Load power factor is unity
(c) Both A&B
(d) None
O.C test: field current = 12.5 A, Voltage between lines =420V
SC test: field current = 12.5 A, line current = rated value.
(d) Current
Calculate the voltage regulation of alternator at 0.8 power factor lagging
16). Induction motor works on the principle of
a. Mutual induction
b. Ampere's law c. Lenz's law
d. Ohm's law
17). The rotor speed of induction motor is always slightly
a. Less than synchronous speed
b. More than synchronous speed
c. Less than slip speed
d. More than slip speed
18). The operating speed of induction motor never be equal to
a. Synchronous speed
b. Slip speed
c. Stator speed
d. Speed of magnetic field
19). An Induction motor is
a. Self-starting with low torque
b. Self-starting with zero torque
c. Self-starting with high torque
d. Non- Self starting
20). In case of induction motor the torque is
a). Directly proportional to slip
b). inversely proportional to slip
c). Directly proportional to square of the slip d). inversely proportional to square of the slip
21). Induced e.m.f in an alternator is
(a) Dynamical induced e.m.f
(b) neither statically nor dynamical
(c) Statically induced e.m.f
(d) Both statically and dynamical
22). the torque is zero, when
a). Slip is zero
b). Slip is unity
c). Slip is infinity
d). Slip is 0.5
23). The condition for the maximum torque occurs when the slip is equal to
a). ratio of rotor resistance and leakage reactance b). ratio of leakage reactance to rotor
c). rotor resistance
d). leakage reactance
24)In an induction motor the core losses occur mainly in
a). Stator core
b). Armature core
c). Slip rings
d). Brushes
25). The maximum torque is also called
a). Pull-out torque
b). Starting torque
c). Running torque
d). Stator torque
26).In induction motor, the maximum efficiency occurs, when
a. Variable losses equal to constant losses
b. Variable losses are equal to zero
c. Constant losses are equal to zero
d. The total losses equal to zero
27). The induction motor is a
a. Self starting motor
b. Not self starting motor
c. Coupled to other drive d. Coupled to other drive
28). The salient type rotor is also called
a. Projected type b. cylindrical type
c. Conical type
d. Spherical
UNIT-IV
1). Valence electronics are the
(a) Loosely packed electronics
(b) Mobile electronics
(c) Electronics present in the outermost orbit
(d) All the above
2). the element having four valence electronics is
(a) Silicon
(b) Germanium
(c) Both (a) and (b)
(d) None of the above
3). the donor impurity element is
(a) Aluminium
(b) Boron
(c) Phosphorus (d) Indium
4). the acceptor impurity element is
(a) Antimony
(b) Gallium
(c) Arsenic
(d) Phosphorus
5). the element which does not have five valence electronics is
(a) Antimony
(b) Arsenic
(c) Gallium
6). A PN-junction diode
(a) Has high resistance in both forward and reverse directions
(d) Phosphorus
(b) Has low resistance in the forward direction
(c) Has high resistance in the forward direction
(d) Has low resistance in the reverse direction
7). In a PN-junction, the region containing the uncompensated acceptor and donor ions is called
(a) Transition zone
(b) Depletion region (c) Neutral region
(d) Active region
8). In a forward biased PN-junction diode the
(a) Positive terminal of the battery is connected to the P side and the negative side to the N side
(b) Positive terminal of the battery is connected to the N side and the negative side to the P side
(c) N side is connected directly to the P side
(d) Junction is earthed
9).Zener diode is usually operated
(a) In forward bias
(c) Near cut-in voltage
(b) In reverse bias
(d) In forward –linear region
10). which of the following diodes is used for voltage stabilization
(a) PN-junction (b) Tunnel
(c) Zener
(d) Varactor
11). Majority carries are in p-type semiconductors.
(a). Protons
(b). Electrons
(c). Holes
(d). Neutrons
12). Majority carries are in N-type semiconductors.
(a). Holes
(b). Protons
(c). Electrons
(d). Neutrons
13). A PNP transistor is made of
(a). Silicon
(b).Germanium (c) both (d). None
14). Conventional biasing of a bipolar transistor has
(a). EB forward biased and CB forward biased
(b). EB reversed biased and CB forward biased
(c). EB forward biased and CB reverse biased
(d). EB reversed biased and CB reversed biased
15). In an NPN transistor, if both the emitter junction and collector junction are reverse biased, the transistor
will operate in
(a). Active region
(b). Saturation region
(c). Cut-off region
(d). Inverted region
16). In an normally biased NPN transistor, the main current crossing the collector junction is
(a). A drift current
(c). A Diffusion current
(b). A hole current
(d). Same as the base current
17). In a transistor, the region that is very lightly doped and very thin is the
(a). Emitter
(b). Base
(c). Collector
(d). None of the above
18). In an NPN transistor, the emitter
(a). Emits or injects holes into the collector (b). Emits or injects electrons into the collector
(c). Emits or injects electrons into the base
(d). Emits or injects holes into the base
19). In an NPN transistor, when the emitter junction is forward biased and the collector junction is reverse
biased, the transistor will operate in the
(a). Active region
(b). Saturation region
(c). Cut-off region
(d). Inverted region
20). Which of the following statements is true?
(a). FET and BJT, both are unipolar
(b). FET and BJT, both are bipolar
(c). FET is a bipolar and BJT is unipolar
(d). FET is a unipolar and BJT is bipolar
UNIT-V
1). Vertical amplifier in CRO is also known as Y-amplifier
2). The shape of a waveform used as the time base is saw tooth waveform
3). The order of voltage required for accelerating the electron beam deflect and sweep is of the order of kv
4). Triggering of the signal in CRO is done to get true representation of input signal
5). The type of electron emission that takes place in a CRT is thermionic emission
6). Scale markings provided on the front side of the CRT screen are called graticules
7). The control knob level in a CRO is used to DC offset voltage adjustment
8). The two types of storage techniques used in analog CROs are Mesh storage,phosphor storage
9). In a cathode ray tube ,the focusing anode is located between pre accelerating and accelerating anodes
10).The source of an electron emission in a cathode ray tube isAverage value barium and strontium oxide coated
cathode.
11).An aquadag is used in a CRO to collect a)primary electrons b)secondary electrons c) both primary and
secondary d)none.
12).Lissajious patterns are used to measure ---------------- and ------------ with CRO
13).The expression for electrostatic deflection sensitivity SE = ---------------14).In CRT ,the vertical deflection plates are placed a)horizontally b)vertically c)uniformly d)none
15).In CRT,the horizontal deflection plates are placed a)horizontally b)vertically c)uniformly d)none
16).In CRT, the fluorescent screen is coated with a)zinc or the silicate b)zinc tungstate c)zinc sulphate d) zinc.
cadmium sulphide.
17). Delay line is used to delay the signal for some time in the horizontal sections. a)True b)False.
18).If a positive potential is applied to the vertical deflection plates, then the beam on the screen moves upwards.a)
True b)False.
19)The voltage which varies linearly with respect to time is appled to a vertical amplifier. a)True b)False
20).The time base of an oscilloscope is developed by sawtooth waveform a)True b)False.
21).Display is possible ina CRO, because of a)CRO b)CRT C)power supply d)accelerating mode