Basic Electrical Object type

Note Book

Electrician Trade

<<Note Book Electrician>>

Home

Objective Questions on General Electrical Engineering

Insulated cables are usually rated by their :
1. operating voltage.
2. operating voltage and highest operating temperature.
3. operating temperature.
4. cost.
Ans: 2
What is cable tray?
1. Cable tray is a cover for many insulatated cables.
2. Cable tray is a protective layer.
3. Cable tray is a rating of cables.
4. Cable tray is a metalic sheild used to protect cables.
Ans: 1
_________ cannot sustain much voltage fluctuations.
1. Sodium vapour lamp.
2. Mercury vapour lamp.
3. Incandescent lamp.
4. Fluorescent lamp.
Ans: 3
Class B insulators can bear temperature (in degree centigrade) upto
1. 130.
2. 120.
3. 105.
4. 90.
Ans: 1
Excess 3 code is known as?
1. Weighted code.
2. Cyclic redundancy code.
3. Self complementing.
4. Algebraic code.
Ans: 3
Permittivity of free space is equal to
1. 8.854 × 10-09 F/m.
2. 8.84 × 10-12 F/m.
3. 9 × 1009 F/m.
4. 1 F/m.
Ans: 2
Capacitor banks are connected with ac induction motor
1. in parallel.
2. in series.
3. not connected at all.
4. can be connected either way –series / parallel.
Ans: 1
By looking at which part of the motor it can be easily confirmed that a particular motor is D.C motor?
1. Frame.
2. Shaft.
3. Commutator.
4. Stator.
Ans: 3
In regenerative braking which of the following is true?
1. Motor energy is dissipated as heat.
2. Motor energy is dissipated in armature heating.
3. Motor energy is dissipated in windage losses.
4. Motor is made to run as generator.
Ans: 4
Which of the following statements regarding single-phase induction motor is correct?
1. It requires only one winding.
2. It can rotate in one direction only.
3. It is self starting.
4. It is not self starting.
Ans: 4
25 kV, 50 Hz, 1 - φ supply is used for supplying power to the locomotives throughout India except which zone ?
1. West.
2. East.
3. South.
4. North-East.
Ans:1
Three resistors, each of R ohms, are connected to form a triangle. The resistance between any two terminals will be
1. 3 / 2 R.
2. 2 / 3 R.
3. R / 2.
4. 3R.
Ans: 2
A 100 W bulb is connected in series with a room heater. If now 100 W bulb is replaced by a 40 w bulb, the heater output will
1. decrease.
2. increase.
3. remain the same.
4. unjustified.
Ans: 1
Which of the following statements is false in case of a series circuit?
1. The current flowing through each resistor is the same.
2. The voltage drop across each resister is same.
3. Resistors are additive.
4. All of above are false.
Ans: 2
Which of the following quantities are same in all parts of a series circuit?
1. Current.
2. Resistance.
3. Voltage.
4. Power.
ans:1
Conductance is the reciprocal of what?
1. Resistance.
2. Inductance.
3. Reluctance.
4. Capacitance.
Ans : 1
You have to replace 1500 Ω resistor in radio. You do not have any 1500 Ω resistor but have several 1000 Ω ones which way you would connect them ?
1. Two in parallel.
2. Two in parallel and one in series.
3. Three in parallel.
4. Three in series.
Ans: 2
Bulbs in street lightning are all connected in which format?
1. Parallel.
2. Series.
3. Series-parallel.
4. End to end.
Ans: 2
1 newton metre (N - m) = ?
1. One watt.
2. One joule.
3. One joule second.
4. Five joules.
Ans: 2
In a delta network each element has value R. The value of each element in equivalent star network will be equal to
1. R / 6.
2. R /4.
3. R / 2.
4. R / 3. Ans: 4

The common voltage across parallel branches with different voltage sources can be determined by the relation V = (V1 / R1 + V2 / R2 + V3 / R3) / ( 1 / R1 + 1 / R2+1 / R3 .....) The statement is associated with which theorem ?
1. Superposition theorem.
2. Thevenin’s theorem.
3. Norton’s theorem.
4. Millman’s theorem.
Ans: 4
The number of independent equations to solve a network is equal to
1. number of chords.
2. number of branches.
3. sum of number of branches and chords.
4. sum of number of branches , nodes and chords.
Ans:1
Which of the following is not a vector quantity?
1. Linear momentum.
2. Angular momentum.
3. Electric field.
4. Electric potential.
Ans:4
What is the dielectric constant of mica ?
1. 200.
2. 100.
3. 3-8.
4. 1-2.
Ans:3
Magnetic moment is a
1. pole strength.
2. universal constant.
3. scalar quantity.
4. vector quantity.
Ans:4
Temporary magnets are used in which of the following ?
1. Loud speakers.
2. Generators.
3. Motors.
4. All of these.
Ans:4
Autotransformer makes effective saving on copper and copper losses, when its transformation ratio is equal to
1. approx to one.
2. less than one.
3. greater than one.
4. none of the above.
Ans:1
The noise resulting from vibrations of lamination set by magnetic forces, is termed as
1. magnetostriction.
2. boo.
3. hum.
4. zoom.
Ans:3
In circle diagram for induction motor, diameter of circle represents which of the following ?
1. Slip.
2. Rotor current.
3. Running torque.
4. Line voltage.
Ans:2
Tarapur nuclear power plant has which type of reactor?
1. Pressurized water reactors.
2. Boiling water type.
3. CANDU type reactors.
4. None of these.
Ans:2
Inside a hollow conducting sphere
1. electric field is zero.
2. electric field is a non zero constant.
3. electric field changes with magnitude of the charge given to the conductor.
4. electric field changes with distance from the center of the sphere.
Ans:1
Two infinite parallel metal plates are charged with equal surface charge density of the same polarity. The electric field in the gap between the plates is
1. same as that produced by one plate.
2. double the field produced by one plate.
3. dependent on coordinates of field points.
4. zero.
Ans:4
As a result of reflection from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater than the velocity of light in space. This is called the
1. velocity of propagation.
2. normal velocity.
3. group velocity.
4. phase velocity.
Ans:4
Length of the cable is doubled, its capacitance C will be
1. one-fourth.
2. one-half.
3. double.
4. unchanged.
Ans:3
————- is the most detrimental impurity in the magnetic materials
1. Carbon.
2. Sulphur.
3. Oxygen.
4. Nitrogen.
Ans:1
The chemical effect of current is used in
1. D.C ampere hour meter.
2. D.C ammeter.
3. D.C energy meter.
4. none of the above.
Ans:1
Swamping resistance is used to compensate
1. error due to temperature true variations.
2. compensate error due to strong magnetic field.
3. both A and B.
4. none of these.
Ans:1
———– was the first city in India to adopt electric traction.
1. Delhi.
2. Madras.
3. Calcutta.
4. Bombay.
Ans:4
Unit of deflection sensitivity of a CRO is
1. V / mm.
2. meter / volt.
3. mm per mV.
4. mm / V.
Ans:2
Null type recorders are
1. bridge recorders.
2. LVDT recorders.
3. potentiometric recorder.
4. any one of the above.
Ans:3

_______ is used to measure the flow of air around aeroplane.
1. Anemometer.
2. Venturimeter.
3. Orifice.
4. nucleus.
Ans: 1
Relative permittivity can be measured by _______ bridge
1. Wheatstone's.
2. Hay's.
3. Desauty's.
4. Schering's.
Ans: 4
There is a ________ between two nodes of signal flow graph
1. link.
2. branch.
3. tree.
4. none of the above.
Ans: 2
What is the phase difference between two windings of A.C servomotor ?
1. 30°.
2. 60°.
3. 90°.
4. 120°.
Ans: 3
Which of the following logic circuits is the fastest?
1. RTL.
2. DTL.
3. TTL.
4. All have same speed.
Ans: 3

Which of the following is not a transmission medium?
1. Telephone lines.
2. Coaxial cables.
3. Modem.
4. Microwave systems.
Ans: 3
In a RC phase shift oscillator, the minimum number of R-C networks to be connected in cascade will be
1. one.
2. two.
3. three.
4. four.
Ans: 3
A three phase 400 V, 6 pole, 50 Hz, squirrel cageinduction motor is running at a slip of 5%. The speed of stator magnetic field with respect to rotor magnetic field and speed of rotor w.r.t stator magnetic field are
1. zero , - 50 rpm.
2. zero, 950 rpm.
3. 1000 rpm, - 50 rpm.
4. 1000 rpm, 950 rpm.
Ans: 1
A 400 V, 50 Hz, 30 Hp, three phase IM is drawing 50 A current at 0.8 p.f lagging. The stator and rotor copper losses are 1.5 KW and 900 W respectively. The friction and windage losses are 1050 W and core losses are 1200 W. The air gap power of the motor will be
1. 23.06 kW.
2. 24.11 kW.
3. 25 kW.
4. 26.21 kW.
Ans: 3
What is the rms value of the voltage waveform shown in Figure ?
diagram-for-mcq
1. 200 /p V.
2. 100 /p V.
3. 200 V.
4. 100 V.
Ans: 4
A galvanometer with a full scale current of 10 mA has a resistance of 1000 Ω. The multiplying power (the ratio of measured current to galvanometer current) of 100 Ω shunt with this galvanometer is
1. 110.
2. 100.
3. 11.
4. 10.
Ans: 3
Assume that diode D1, D2 in figure are ideal diodes. The value of current is
mcq-diagram
1. 0 mA.
2. 0.5 mA.
3. 1 mA.
4. 2 mA.
Ans: 1
India’s largest thermal power station is located at
1. Kota.
2. Sarni.
3. Chandrapur.
4. Neyveli.
Ans: 3
Oxide film arrestor has which of the following properties?
1. Does not require daily charging.
2. Installed at points of transmission line where daily visit is difficult.
3. Expensive.
4. Both A and B.
Ans: 4
How many classes of insulating materials are there?
1. 6.
2. 7.
3. 5.
4. 8.
Ans: 2
What are insulating materials that can tolerate maximum temperature?
1. Mica.
2. Porcelain.
3. Glass.
4. All of these.
Ans: 4
The current through the 2 KΩ resistance ( rest resitances are all 1 ohm each ) in the circuit shown in diagram
1. 0 mA.
2. 1 mA.
3. 2 mA.
4. 6 mA.
Ans: 1
What is the total installed power capacity (MW) in West Bengal as published by ministry of power in 2011?
1. 6114.05.
2. 10000.32.
3. 8113.27.
4. 15515.22.
Ans: 3
What should be the minimum depth (in metre)of cable trench to dug for laying of 1.1 kV?
1. 0.75.
2. 0.90.
3. 1.05.
4. 1.20.
Ans: 1
What is the dielectric material used in precision small value capacitor and capacitor used in radio frequency circuits?
1. Oil impregnated paper.
2. Glass.
3. Vacuum ,air.
4. Titanium oxide.
Ans: 3

ALNICO is an alloy of
1. iron, aluminium.
2. aluminium, nickel.
3. iron, cobalt, nickel.
4. aluminium, nickel, iron and cobalt.
Ans: 4
What is the name of the fluorescent material that gives red colour fluorescence?
1. Zinc silicate.
2. Calcium silicate.
3. Zinc sulphide.
4. Magnesium silicate.
Ans; 4
NTPC (National Thermal Power Cooperation) has its only thermal power generating unit in West Bengal at
1. Durgapur.
2. Bakreshwar.
3. Farakka.
4. Katwa.
Ans: 3
Choose the best suitable of Diamagnetic : Paramagnetic::
1. Water: Air.
2. Iron: Steel.
3. Permalloy: Super-alloy.
4. Nickel: Cobalt.
Ans: 1
Find the odd one out.
1. Absorptivity.
2. Emissivity.
3. Refractive index.
4. Dielectric strength.
Ans: 4
Which of the following is the least desired property in magnetic materials for electrical engineering applications ?
1. High magnetic permeability.
2. High electrical resistivity.
3. Large hysteresis loop.
4. All of the above.
Ans: 3
Cryogenics is a branch of science dealing with which of the following?
1. High temperature.
2. Low temperature.
3. Friction and wear.
4. Crystal growth.
Ans: 2

or making a capacitor it is better to select a dielectric having
1. low permittivity.
2. high permittivity.
3. permittivity same as that of air.
4. permittivity more than that of air.
Ans: 2
An electrolytic capacitor can be used for
1. DC only.
2. AC only.
3. both A and B.
4. none Of the above.
Ans: 1
There are two capacitors C1 and C2 in parallel , what will be their equivalent capacitance?
1. (C1 + C2) / C1C2.
2. (C1C2) / C1 + C2.
3. C1 + C2.
4. C1C2.
Asns: 3

What is form factor?
1. Average value / R.M.S. value.
2. Average value / Peak value.
3. Instantaneous value / Average value.
4. R.M.S. value / Average value.
Ans: 4
Select the wave that has the least value of form factor.
1. Square wave.
2. Rectangular wave.
3. Triangular wave.
4. Sine wave.
Ans: 1
What is the frequency of domestic power in India?
1. 50 Hz.
2. 60 Hz.
3. 220 Hz.
4. 70 Hz.
Ans; 1
What is apparent power in AC operation?
1. Product of voltage and current.
2. Product of rms volatge and rms current.
3. Product of voltage and current at no load.
4. Product of voltage and current at full load.
Ans; 2
What is the real power in AC operation?
1. VIcosφ.
2. Apperant power × cosφ.
3. Both option A & B.
4. None of these.
Ans: 3

Sulphation in a lead acid battery occurs due to
1. heavy charging.
2. fast charging.
3. trickle charging.
4. incomplete charging.
Ans: 4
Capacitors for P.f correction are rated in
1. KW.
2. KVA.
3. KV.
4. KVAR.
Ans: 4
Among the options which metal has the highest electrical conductivity?
1. Aluminium.
2. Stranded aluminium.
3. Copper.
4. Steel. Ans: 3

If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400 : 5, then plug setting multiplier will be
1. 10 A.
2. 15 A.
3. 25 A.
4. 50 A.
Ans: 1
The high torque to weight ratio in an analog indicating instrument indicates
1. low friction loss.
2. high friction loss.
3. nothing related to friction loss.
4. none of these.
Ans: 1
Which of the following load normally needs starting torque more than rated torque?
1. Blowers.
2. Conveyers.
3. Air compressors.
4. Centrifugal pumps.
Ans: 2

The numberof atoms per unit cell in a B.C.C structure is
1. 7.
2. 4.
3. 2.
4. 12.
Ans: 3
Class B amplifier is biased
1. at midpoint of load line.
2. just at cut-off.
3. nearly twice cut-off.
4. none of the above.
Ans: 2
What is called the instantaneous value of an alternating current?
1. The value of alternating quantity at any instant.
2. The value of peak quantity at any instant.
3. The value of peak current at any instant.
4. The value of alternating frequency at any instant.
Ans: 1
What is called a cycle in case of AC operation ?
1. When ac completes the (+)ve half, is called a cycle.
2. When ac goes through a complete (+)ve to (-)ve, is called a cycle.
3. When an alternating quantity completes the (–)ve cycle, is called a cycle.
4. Option A and C both.
Ans: 2
Which of the following state capital is not on broad gauge track?
1. Lucknow.
2. Bhopal.
3. Jaipur.
4. Chandigarh.
Ans: 3
Candela is the unit of what?
1. Wavelength.
2. Luminous intensity.
3. Luminous flux.
4. Frequency.
Ans: 2
Solid angle is expressed in terms of
1. radians / meter.
2. radians.
3. steredians.
4. degree.
Ans: 3
A square matrix is called singular if its
1. determinant is zero.
2. determinant is unity.
3. determinant is infinity.
4. rank is unity.
Ans: 1
In a series resonant circuit impedance is
1. minimum.
2. maximum.
3. zero.
4. none of these.
Ans: 1
In single phase rotary converter the number of slip rings will be
1. two.
2. three.
3. four.
4. six.
Ans: 1
What is time period T?
1. Time taken by an alternating quantity to complete the (+)ve half.
2. Time taken by an alternating quantity to complete the a cycle.
3. Time taken by an alternating quantity to complete the (-)ve half.
4. Time taken by an alternating quantity to reach the peak value.
Ans: 2
What is called the frequency in AC operation?
1. No. of (+)ve quadrature made per second.
2. No. of cycles made per second.
3. No. of (-)ve quadrature made per second.
4. No. of wave made per second.
Ans; 2

Do you know the resistance of human body ?
1. 5 Ω.
2. 25 Ω.
3. 250 Ω.
4. 1000 Ω.
Ans: 4
Out of the following which is a poor conductor?
1. Cast iron.
2. Stainless steel.
3. Carbon.
4. Tungsten.
Ans: 2
The four bulbs of 40 W each are connected in series with a battery across them, which of the following statement is true?
1. The current through each bulb is same.
2. The voltage across each bulb is not same.
3. The power dissipation in each bulb is not same.
4. None of the above.
Ans; 1
Which of the following quantities remain same for all parts of a series circuit?
1. Voltage.
2. Current.
3. Power.
4. Resistance.
Ans: 2

<span style= "font-size: 18px;"><strong><ins>&amp;amp;lt;span style= "font-size: 18px;"&amp;amp;gt;&amp;amp;lt;strong&amp;amp;gt;&amp;amp;lt;ins&amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;span style= "font-size: 18px;"&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;strong&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;strong style= "color: #541201;"&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;span style="color: #13207a;"&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;An ideal voltage source should have&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/strong&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/strong&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;lt;/ins&amp;amp;gt;&amp;amp;lt;/strong&amp;amp;gt;&amp;amp;lt;/span&amp;amp;gt;</ins></strong></span>
1. large value of emf.
2. small value of emf.
3. zero source resistance.
4. infinite source resistance.
Ans; 3
Which of the following is a bilateral element?
1. Constant current source.
2. constant voltage source.
3. capacitance.
4. none of the above.
Ans : 3
Electric field intensity (E) at ant point in an electric field is equal to
1. potential gradient.
2. (potential gradient)2.
3. (potential gradient)1/2.
4. (potential gradient)1/3.
Ans: 1
The essential condition for parallel operation of two D.C generators is that they have
1. same KW rating.
2. same operation r.p.m.
3. same dropping voltage characteristics.
4. same percentage regulation.
Ans: 3
Plug setting of a relay can be altered by varying
1. air gap of magnetic path.
2. no. of ampere-turns.
3. adjustable back up stop.
4. none of these.
Ans: 2
Galvanised steel is generally used as
1. stray wire.
2. earth wire.
3. structural components.
4. all of the above.
Ans: 4

What is the relation between time period T and frequency?
1. T = 1 / frequency.
2. T = 0.5 / frequency.
3. T = 0.85 / frequency.
4. T = frequency.
Ans: 1
What is referred as the average value in AC opearation?
1. Average of all values of an alternating quantity.
2. Average of all values of the phase sequences.
3. Average of all values of the (+)ve and (-)ve half.
4. Average of all values of an alternating quantity over a complete cycle.
Ans: 4

Sri Neelakanteswara ITI