Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields

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Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields 1. A 2 ohms resistor having 1 ampere current will dissipate the power of a) 2 Watts b) 2 Joules c) 1 Watt d) 1 Joule Ans: (a) 2. When 2 volts e.m.f. is applied across a 1 farad capacitor, it will store the energy of

a) 2 Joules b) 2 Watts c) 4 Joules d) 1 Watt Ans: (a) 3. Thevenin’s equivalent circuit can be used to calculate the power loss in the original circuit.

a) True b) False Ans: (a) 4. A 1 H inductance carrying the current of amperes will store the energy o f

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a) 2 Watts b) 2 Joules c) 4 Watts d) 4 Joules Ans: (b) 5. An electrical circuit with 10 branches and 7 junctions will have

a) 10 loop equations b) 4 loop equations c) 3 loop equations d) 7 loop equations Ans: (b) 6. An electrical circuit with 8 independent nodes will have

a) 10 node equations b) 4 node equations c) 3 node equations d) 7 node equations Ans: (d) 7. If two winding having self-inductances L1 and L2, and a mutual inductance m are connected in series will opposite, then the total inductance of series combination will be

a) L1 + L2 - 2M b) L1 + L2 + 2M c) L1 - L2 + 2M d) L1 + L2 – – M M



















a) Current b) Voltage c) Power d) None of the above Ans: (b) 9. The power factor at resonance in R-L-C parallel circuit is

a) 0.5 lagging b) 0.5 leading c) Unity d) Zero Ans: (c) 10.An inductive circuit resistance 2 ohms and inductance 0.5 H is connected to a 250 volts, 50 Hz supply. What capacitance will be placed in parallel to produce resonance?

a) 700 micro-farad b) 750 micro-farad c) 701 micro-farad d) 714 micro-farad e) 711 micro-farad Ans: (d) 11. The current in resonance in parallel L-C circuit will be

a) Very small b) Very high c) Zero d) Infinity



















a) A galvanometer with low resistance in series is an ammeter b) A galvanometer with high resistance in series is an ammeter c) A galvanometer with high resistance in parallel is a voltmeter d) A galvanometer with low resistance in parallel is a voltmeter Ans: (a) 13. The time constant of the capacitance circuit defined as the time during which voltage

a) Rises to 63.2% of its final steady value b) Rises to 38.6% of its final steady value c) Falls to 36.8% of its final steady value d) None of the above Ans: (a) 14. Which of the following equation is Poisson’s equation?

a) d2V/dx2 + d2V/dy2 + d2V/dz2 = 0 b) d2V/dx2 = - p/ε0 c) d2V/dx2 + d2V/dy2 = 0 d) d2V/dx2 + d2V/dy2 = p/ε0 Ans: (b) 15. The circuit whose properties are same in either direction is known as

a) Reversible circuit b) Irreversible circuit c) Unilateral d) Bilateral circuit Ans: (d)



















a) Has no current source b) Has no e.m.f. source c) Has neither of the above d) Has either of the above Ans: (b) 17.If an electrical network having one or more than one voltage sources is transformed into equivalent electrical network with a single voltage source (which is open circuit voltage of previous circuit) with series internal resistance resistance of the network with all voltage sources replaced by their internal resistances.

The above illustration is called a) Reciprocity theorem b) Thevenin’s theorem c) Superposition theorem d) Duality Ans: (b) 18. In the circuit given below, the ammeter reads 0.1 ampere and voltmeter 10 volts. The internal resistance of the ammeter is 1 ohm and that of voltmeter is 500 ohms. What is the value of R?

a) 110 ohms b) 120 ohms c) 115 ohms d) 112.5 ohms e) 125 ohms Ans: (e) 19.In the circuit given below the power factor will be



















d) Unity, Ans: (b) 20. If a = 4 < 20° and b = 2 < 10° then the value of a/b, will be :

a) 2 < 10° b) 2 < 30° c) 2 < -10° d) 2 < 20° Ans: (a) 21. The conjugate of the complex quantity (a + jb) will be

a) – a) – a a – – jb jb b) – b) – a a + jb c) A - jb d) Ja – Ja – b b Ans: (c) 22. Mass in the MKS unit system s ystem is analogous to

a) Resistance b) Voltage c) Inductance d) Capacitance Ans: (d) 23.A damped oscillation has the equation I = 50 e-10tsin 628 t. What will be the frequency frequenc y of a oscillation?





















d) 60 Hz Ans: (c) 24. In a loss-free R-L-C circuit the transient current is

a) Sinusoidal b) Oscillating c) None-oscillating d) Square wave Ans: (a) 25. A 0.5 meter long conductor carrying a current of 2 amperes is placed in a magnetic field having the flux density of 0.05 wb/m2. What will be the amount of force experienced by the conductor?

a) 1 New b) 2 New c) 0.05 New d) 0.5 New Ans: (c) 26. Two parallel conductors carry the same current in the same direction. What kind of mutual force they will experience?



















a) The flow of current in the electric circuit involves discontinuous expenditure of energy. b) The flow of current in the electric circuit requires energy for creating the current but not to maintain it. c) In the magnetic circuit energy is needed continuously to maintain the flux. d) In the magnetic circuit energy is needed for creating the flux initially but not to maintain it. Ans: (c) 28. If a coil has a resistance of 10 ohms and an inductance indu ctance of 1 H, what will be the value of current 0.1 second after switching on a 500 V d.c. supply?

a) 6.32 A b) 3.16 A c) 3.7 A d) 4.0 A Ans: (b) 29. The r.m.s. value of an alternating current is given by steady (d.c) current which when flowing through a given circuit for given time produces p roduces

a) The same heat as produced by a.c. when flowing through the same circuit b) The less heat than produced by a.c. when flowing through the same circuit c) The more heat than produced by a.c. when flowing through the same circuit



















Ans: (b) 31. The average value of the alternating current is more than the r.m.s. value a) True b) False Ans: (b) 32. The amplitude factor of sinusoidal voltage is

a) 1.11 b) 1.57 c) 1.414 d) 0.637 e) 0.707 Ans: (c) 33. An electrical circuit is shown below, what will be the power dissipation in the circuit assuming P as power across R 2 ?

a) 3/4 P b) 2/3 P c) 4/3 P



















Ans: (b) 35. If two resistances connected in parallel and each dissipates 10 watts the total power supplied by the voltage source equals

a) 5 watts b) 10 watts c) 20 watts d) 100 watts Ans: (c) 36. If a parallel circuit is open in the main line, the current

a) Increases in each branch b) Is zero in all branches c) Is zero in the highest resistive branch d) Increases in the branch of the lowest resistance Ans: (b) 37. In a series parallel circuit, any two resistances in the same current path must be in

a) Parallel with each other b) Parallel with the voltage source



















d) An IR drop equal to the applied voltage Ans: (c) 39. In which of the following circuits most current will be produced by the voltage source?

a) 5 volts across a 5 ohm resistance b) 5 volts across two 5 ohm resistance in series c) 5 volts across two 5 ohm resistance in parallel d) 500 volts across a 1 M Ω resistance Ans: (c) 40. There 60 watt bulbs are in parallel across the 60 volt power line. If one bulbs burns open

a) Rest of the two bulbs will not light b) All three bulbs will light c) The other two bulbs will light d) There will be heavy current in the main line Ans: (c) 41. If a wire conductor of 0.1 ohm resistance is doubled in length, its resistance becomes

a) 0.1 ohm b) 0.02 ohm





















d) About 5 ohms per degree Ans: (c) 43. The square waveform of current has following relation between r.m.s. value and average value

a) R.M.S. value of current is greater than the average value b) R.M.S. value of current is less than the average value c) R.M.S. value of the current is to average value d) There is no meaning of r.m.s value and average value for square wave Ans: (c) 44. There are not transient in i n resistive circuits.

a) True b) False



















47. The double energy transients occur in the

a) R-L circuit b) R-C circuit c) Pure inductive circuit d) R-L-C circuit Ans: (d) 48. A closed switch has a resistance of

a) Infinity b) Zero c) About 500 ohms d) About 50 ohms at room temperature Ans: (b) 49. The ionization current in the liquids and gases results from



















51. A resistor is connected across a 45 volt battery to provides 13 mA of current. The required resistance with suitable wattage rating will be

a) 4.5 ohms, 1 watt b) 45 ohms, 10 watts c) 1000 ohms, 2 watts d) 45,000 ohms, 1/3 watt Ans: (d) 52. A 2.2 lead acid cell

a) Is a primary cell b) Is a secondary cell c) Has unlimited shelf life d) Has a maximum current rating of about 150 mA Ans: (b)



















55. The Edison cell

a) Is a primary cell b) Uses sulphuric acid electrolyte c) Has 2.5 volts output d) Has nickel and iron electrolyte Ans: (d) 56. The cells are connected in series to

a) Increase the current output b) Increase the voltage output c) Decrease the internal resistance d) Decrease the amount of charging voltage required Ans: (b) 57. A 45-volt source with an internal resistance of 2 ohms is connected across a wire-wound



















59. A magnetic compass point to the

a) Geographical poles b) True north pole c) Magnetic north pole d) Agonic line of the earth filed Ans: (c) 60. If the wire which is vertical to this page p age has electron flow downward the conductor con ductor will have

a) No magnetic field b) A counter-clockwise field in the plane of the power c) A clockwise field in the plane of the paper d) A counter-clockwise field in the plane perpendicular to the paper Ans: (b)





















a) Energy b) Power c) Voltage d) Torque Ans: (d) 64. Motor action in a wire conducting current can be produced

a) Without any additional magnetic field b) Move the conductor from weaker field toward stronger field





















a) 1-amp. D.c. current b) 50-amp. D.c. current c) 1-amp. 60 cycles a.c. current d) 1-amp. 490 cycles a.c. current Ans: (d) 68. When the alternating voltage reverses in p olarity, the current its produces

a) Reverses its direction b) Has the same direction





















a) Less than one ohm b) 10.5 ohms c) 104 ohms d) More than 1 M Ω Ans: (b) 72. An open coil has

a) Zero resistance and high inductance b) Infinite resistance and zero inductance





















a) 0° b) 60° c) 45° d) 90° Ans: (c) 76. An arc across the switch opening an R-L circuit is a result is a result of the a) Long time constant b) Large self-induced voltage across the inductance





















a) Maximum value b) Maximum change in magnetic field c) Minimum change in magnetic field d) 0.707 × Peak Ans: (b) 80. Two 300-mh chokes connected in series will have the total inductance of

a) 60 mh b) 300 mh























a) Ceramic capacitors must be connected in the correct polarity b) Electrolytic capacitor must be connected in the correct polarity c) Mica capacitors are available in capacitance value of 1 to 10 micro-farad























87. A steady d.c. voltage is applied to capacitor, after changes to battery voltage, the current in the circuit

a) Depends on the current rating of the battery























a) A line current is maximum b) The total impedance is maximum c) The total impedance is maximum























a) High resonant frequency b) Low resonant frequency c) High Q























a) 500 ohms b) 750 ohms c) 637 ohms

























































































































































































































































































































































































































































































































































a) Resistance b) Inductance c) Capacitance d) None of the above Ans: (b) 241. Which of the following statement is true? a) Div curl B = ∞ b) Div curl A = 0 c) Div curl B = 1 d) Div curl B = B Ans: (b) 242. If X = q/4πr 2, which of the following parameter will be X?

a) Electric field strength b) Magnetic field strength c) Electric displacement density d) Permeability Ans: (c) 243. Which of the following expression is correct for electric field strength?

a) E = D b) E = πD c) E = D/ε d) E = r/ε Ans: (c)



















a) λ/2 b) λ/8 c) 4λ d) λ/4 Ans: (d) 245. Polarization in the electromagnetic waves is attributed to

a) absorptive nature of waves b) reflection of waves c) longitudinal nature of waves d) transverse nature of waves e) electric field of waves Ans: (d) 246. Which of the equation represents the following wavefrom?

a) y = sin x/3 b) x = 2 sin 3x/2 c) y = 2sin 3x d) y = 2 sin 2x e) y = 2 sin x Ans: (c) 247. If 0 < θ 1 < θ2 < π/2, which of the following statement is true ?

a) sin θ1 < sin θ2 b) cos θ1 < cos θ2 c) tan θ1 < tan θ2 d) (a)and (c) only



















Ans: (d) 248. Which of the following statement is true?

a) The magnetic field inside the conductor is zero b) The magnetic field inside the semiconductor is zero c) The magnetic field inside superconductor is zero d) The magnetic field inside the superconductor is zero Ans: (c) 249. Wein Bridge may be used for

a) Resistance determination b) Frequency measurements c) Power factor measurements d) Harmonic distortion analysis e) Both (b) and (d) Ans: (e) 250. The D’Arsonval instruments work on the principle of

a) Moving coil instruments b) Moving iron instruments c) Potentiometric instruments d) Permanent magnet moving coil instruments e) Induction instruments Ans: (d) 251. When any material has negative magnetism, the material is called as



















d) Antiferromagnetic Ans: (b) 252. The bar magnet has

a) The dipole movement b) Monopole movement c) (a) and (c) both d) None of the above Ans: (a) 253. There is no such material which has properties of magnetic monopole.

a) True b) False Ans: (b) 254. Which of the following materials are diamagnetic?

a) Copper b) Silver c) Copper and silver d) Iron Ans: (c) 255. When of the following material fall in the category of paramagnetic materials?

a) Copper b) Iron c) Copper and iron



















Ans: (d) 256. Which of the following type materials are not very important for engineering applications? a) Paramagnetic b) Ferromagnetic c) Diamagnetic d) None of the above Ans: (c) 257. The solids which have small but positive magnetic susceptibility are called

a) Ferromagnetic b) Paramagnetic c) Diamagnetic d) Anti-ferromagnetic Ans: (b) 258. The susceptibility of paramagnetic materials generally lies between

a) 10-3 and 10-7 b) 10-3 and 10-5 c) 10-4 and 10-8 d) 10-2 and 10-5 Ans: (b) 259. For which of the following materials ma terials the saturation value is the highest?





















d) Diamagnetic materials Ans: (a) 260. For which of the following materials ma terials the relative permeability is less than one?

a) Ferromagnetic materials b) Diamagnetic materials c) Paramagnetic materials d) Ferrites Ans: (b) 261. The temperature above which an anti-ferromagnetic material becomes paramagnetic is called

a) Peak temperature b) Critical temperature c) Neel temperature d) Weiss temperature Ans: (c) 262. The inductance of the following circuit across A and B will be

a) L1+L2+M



















d) (L1 L2-M2)/(L1+L2+2M) Ans: (b) 264. The transient currents may occur in following circuits

a) Pure resistive circuits b) Capacitive circuits c) RL circuits d) RLC circuits e) (b) or (c) or (d) Ans: (e) 265. Which of the following coil will have large resonant frequency?

a) A coil with large distributed capacitance b) A coil with low distributed capacitance c) A coil with large resistance d) A coil with low resistance Ans: (a) 266. The transfer matrix |1&0 Y&1| belongs to wh ich of the following circuits? 267. What will be the magnetic field in the toroid having N number numb er of turns, diameter d and current I



















269. Atypical radar antenna will have the bandwidth of

a) 4° b) 6° c) 1° d) 2° Ans: (d) 270. Which of the following antenna is non-resonant?

a) Broadside array b) Marconi c) Discone d) Rhombic Ans: (d) 271.Ferrimagnetic materials are generally classified as a) Conductors b) Semiconductors c) Dielectric d) Insulators



















273. The magnetic materials exhibit the property of magnetization because of

a) Orbital motion electrons b) Spin of electrons c) Spin of nucleus d) Either of these e) All of the above Ans: (c) 274. A coil of 0.04 mH is carrying current of 1 A. If this current is reversed in 0.02 seconds, the induced emf in the coil will be

a) 0.16 V b) 0.008 V c) 0.004 V d) 0.04 V Ans: (c) 275. A coil wound on the iron core which carries current I. The self induced voltage in the coil is not affected by

a) Change of number of turns of coil b) The resistance of magnetic path c) Variation in voltage to the coil d) Variation in coil current



















Ans: (c) 277. Which of the following statements is correct?

a) Inductance of the coil carrying a constant DC current will increase the current b) The inductance of the coil carrying a constant DC current will not affect the current c) The inductance of the coil carrying a constant DC current will decrease the current d) The inductance of the coil carrying a constant Dc current will change the current into pulses Ans: (b) 278. If the frequency of power supply is 60 Hz, what will be the period of one cycle?

a) 0.02 sec b) 0.015 sec c) 0.017 sec d) 0.03 sec Ans: (c) 279. If a sinusoidal wave has frequency of 50 Hz with 15 A rms current which of the following equation represents this wave

a) 15 sin 50 t





















d) The current will increase by fourfold Ans: (b) 281. The safest value of current the human body can carry more than 3 seconds is

a) 5 mA b) 15 mA c) 25 mA d) 35 mA e) 9 mA Ans: (e) 282. Which of the following precaution will be taken first if a man suffers from electric shock?

a) Switch the power supply b) Call the doctor c) Make him lie on ground



















a) Volume of material b) Magnetic field c) Frequency d) Either of them e) None of these Ans: (e) 285. For which of the following materials the net magnetic moment should be zero.

a) Ferromagnetic materials b) Diamagnetic materials c) Anti-ferrimagnetic materials d) Anti-ferromagnetic materials Ans: (d) 286. What will happen if strong magnetic field is applied to ferromagnetic field?



















a) The conductivity of ferromagnetic material is better than ferri tes b) The conductivity of ferrites is better than ferromagnetic materials c) The conductivity of ferrites is same as that of ferromagnetic materials d) The conductivity of ferrites is very high Ans: (b) 289. The magnetization and applied field in ferromagnetic materials are related

a) Linearly b) Non-linearly c) Parabolically d) Sinusoidally Ans: (b) 290. The effective power in a pure capacitive circuit shall be

a) Energy stored by capacitor



















a) Reactive power b) True power c) Apparent power d) Reactive and power Ans: (b) 293. In which of the materials the spin moments associated with two sets atoms are aligned antiparallel to each other.

a) Ferromagnetic materials b) Anti-ferromagnetic materials c) Ferrites d) Ferromagnetic materials Ans: (b) 294. Which of the following statements is correct?



















a) Carbon power b) Zinc chloride c) Iron ore and carbon powder d) Ammonia chloride Ans: (c) 297. If the current is passed through a conductor which of the following phenomenon will be observed?

a) The magnetic field will be developed in the conductor b) The magnetic field and heat is developed in the conductor c) The only heat is developed in the conductor d) The molecules of the conductor attract each other Ans: (b) 298. The standing wave ratio of 4 will be applicable to

Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields

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