# Top 300 Electrical Circuits Objective Questions and Answers

In this article, we shared the top 300 electrical circuits objective questions and answers for instrumentation, electrical, and electronics engineering students.

## Electrical Circuits Questions

The below list provides all the multiple-choice questions (MCQ) related to electrical circuits.

Answers are available at the bottom of the article.

1. Which statement is true?

2. The ​ admittance ​ of ​ a ​ parallel ​ RLC ​ circuit ​ ​ is ​ ​ found ​ ​ to ​ ​ be the ​ ___ sum of conductance and susceptances.

3. Which component opposes voltage change?

4. Another term for a superconductor.

5. In calculating maximum instantaneous power ____ voltage or current is used.

6. What is a closed path made of several branches of the network called?

7. It is impossible to change the voltage across a capacitor instantly, as this would produce ​ ​ ____ ​ current.

8. Liquids that are good conductors because of ionization are called

9. When two pure sine waves of the same frequency and the same amplitude which are exactly 180˚ out-of-phase are added together, the result is

10. The temperature-resistance coefficient of pure gold is

11. The presence of an electric current is made known by

12. A trimmer is a variable capacitor in which capacitance is varied by changing the

13. The potential gradient in a cable is maximum in

14. The current is ​____ times the maximum current at half-power points of a resonance curve.

15. In dividing or multiplying phasor quantities,____ form is used.

16. If two equal resistances connected in series across a certain supply are now connected in parallel across the same supply, the ​ power ​ produced ​ will ​ be that of series connection

17. What is the efficiency under the conditions of maximum power transfer?

18. Refers specifically to steady-state values of quantities in ac circuits which are complex numbers.

19. What is considered as the most important value of a sine wave?

20. Electric energy refers to

21. When two complex conjugates are subtracted, the result is a

22. A lead conductor has a resistance of 25​ Ω ​at 0 ˚C. Determine its resistance at -30 ˚C

23. What is the total capacitance of 10 capacitors, each of 20 µF in series?

24. What is the total effective capacitance of two 0.25 µF capacitors connected in series?

25. A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20,000 ohms?

26. Norton’s theorem is what form of an ac equivalent circuit?

27. Which is considered as the effect of a dielectric material?

28. The reciprocal of a complex number is

29. What is a rotating vector whose projection can represent either current or voltage in an ac circuit?

30. If two complex conjugates are added, ___ components results.

31. When the movable plates of a gang capacitor completely overlap the fixed plates, the capacitance of the capacitor is

32. The area of capacitor plates increases two times, then its capacitance

33. The distance between the capacitor plates increases two times, then its capacitance

34. Which of the following is neither a basic physical law nor deliverable from one?

35. What is the peak factor of a triangular wave?

36. In a series circuit with unequal resistances the

37. Which of the following is the statement of Ohm’s law?

38. The usual load of a dc circuit is a/an

39. In an RL series circuit,

40. What is the other name of relative permittivity?

41. A capacitor consists of two

42. What maximum voltage can be applied across the capacitor for a very short period of time?

43. And ideal current source has an internal conductance of ​_____​ siemen(s)

44. If the capacitance of mica capacitor is 5 times the capacitance of air capacitor, then the relative permittivity of mica is

45. The Q-factor of a parallel resonant circuit is also known as

46. What is the reading of an ohmmeter for a shorted capacitor?

47. The symbol Q refers to

48. At what frequency will an inductor of 5mH have the same reactance as a capacitor of 0.1 µF?

49. What is the most convenient way of achieving large capacitance?

50. The Q-factor of a parallel resonant circuit is also known as

51. Which of the following is also known as an anti-resonant circuit?

52. A series-parallel combination of identical resistors will

53. The ratio of the flux density to the electric field intensity in the dielectric is called

54. Which of the following materials has the lowest dielectric strength?

55. What refers to the lowest voltage across any insulator that can cause current flow?

56. What fusion of elements is without chemical action between them?

57. For parallel capacitors, total charge is

58. Which of the following has a positive temperature coefficient?

59. The reason why electrical appliances are connected in parallel.

60. If three 100-pF capacitors are connected in series, then the total capacitance is

61. Rationalizing the denominator of a complex number means

62. An inductor carries 2 A dc. If its inductance is 100 µH, then what is its inductive reactance?

63. The reactance curve is a plot of frequency versus ____ for a series RLC circuit

64. A capacitor requires 12 µC of charge to raise its potential of 3 V. What is the capacitance of the capacitor?

65. An impedance is given by ​90​ ∠-45o is a/an ​ ____ impedance.

66. If resonant frequency is 10 kHz and quality factor is 50, then

67. The internal resistance of an ideal current source is

68. If two resistances of 9​ Ω ​and 6​ Ω ​are connected in parallel, the total resistance is

69. A capacitor is basically constructed of

70. Inductive reactance applies only to sine waves because it

71. The ohmic value of a resistor with a negative temperature coefficient

72. An open inductor has

73. Two complex numbers or phasors are said to be conjugate if they

74. When the frequency of an AC wave decreases, the value of XL in a coil

75. If a capacitor is rated for 200V dc, what is its effective AC working voltage?

76. A coil of inductance L has an inductive reactance of XL in an ac circuit in which the effective current is I. The coil is made from a superconducting material. The rate at which power is dissipated in the coil is

77. Of the equivalent combination of units, which one is not equal to watt?

78. The graph between an alternating quantity and time is called

79. Which one of the following elements serves as a protection against overload?

80. An ac series circuit is composed of resistance of​ 20Ω ​, the inductive reactance of 40​Ω​, and a capacitive reactance of 15​Ω​. If a current of 1 ampere is flowing, what is the applied voltage

81. A trigger circuit consisting of a capacitor of 0.01 µF is connected in series with a resistor. If the circuit requires 100 Vdc to operate, determine the value of the resistor when time constant is 0.009s.

82. Which of the following is a preferred resistor value?

83. Which of the following combination of length and the cross-sectional area will give a certain volume of copper the least resistance?

84. In a resonant circuit, if Q ​≥​10 resonant frequency ______ ​ bandwidth.

85. Which of the following is a common material used in wire-wound resistors?

86. Which of the statements below is not true?

87. What is the most common non-sinusoidal waveform?

88. At what frequency will the current in a series RLC circuit reach its maximum value for an applied voltage of 15 V with R = 500​Ω​, L = 100 µH and C = 0.001 µF?

89. When two in-phase sine waves that have identical frequency and amplitude are added together, then the result is a sine wave with ​____ the amplitude of either.

90. An open resistor when checked with an ohmmeter reads

91. The ratio between the active power and the apparent power of a load in an ac circuit is called

92. The internal resistance of an ideal voltage source is

93. A capacitance of 6 µµF means

94. In the 5-band method of capacitor color coding, the first band indicates

95. Which of the following is the most popular waveform?

96. In an ac circuit, the power dissipated as heat depends on

97. The ratio of maximum value to the effective value of an alternating quantity is called

98. A series circuit has a ____ power factor at its half-power points

99. A linear circuit is one whose parameters

100. The capacitor opposes any change in voltage across it by

101. Conventional flow assumes charges flow from

102. What is the reciprocal of quality factor?

103. Which of the following elements is active?

104. A real current source has

105. Which factor does not affect resistance?

106. Points to be considered in choosing a capacitor

107. What is the specific resistance of a pure germanium?

108. In a rectangular wave, the peak factor is

109. For multi-plate capacitor, capacitance is proportional to

110. A resistor wound with a wire doubled back on itself to reduce the inductance.

111. What theorem is usually used in the analysis of the transistor circuit?

112. What theorem is generally used in the analysis of vacuum tubes?

113. Which of the following is not a factor affecting dielectric strength?

114. What refers to such work at very low temperatures, near absolute zero?

115. In adding or subtracting phasor quantities, ____​ form is the most convenient.

116. An electric circuit contains

117. If the voltage across the plates of 2 F capacitor is increased by 4 V, then charge on the plates will

118. What is the total resistance of a two equal valued resistors in series?

119. The charge in the capacitor is stored at the

120. The voltage lags the current by​ π/2 ​cycle in a

121. What is the purpose of a load in an electric circuit?

122. How many coulombs are delivered by a storage battery in 25 hours if it is supplying current at the rate of 3 A?

123. Which of the following capacitors has the highest cost per µF?

124. The curve between current and frequency is termed as

125. A capacitor of 0.5 µF charged to 220 V is connected across an uncharged 0.5 µF capacitor. What is the voltage across each capacitor?

126. Leakage resistance in a capacitor results into

127. Effects of capacitance

128. A capacitor opposes change in

129. Another term of the quality factor of the resonant circuit.

130. What is the value of a carbon composition resistor with the following color code: Brown, white, orange, red

131. In a complex resistance-reactance plane,​ XL ​is represented

132. What determines the direction of induced emf in a conductor or coil?

133. What is the temperature coefficient of the resistance Eureka?

134. What is the conductance of a circuit having three 10​Ω ​resistors in parallel?

135. A tank circuit is a

136. A term used to express the amount of electrical energy stored in electrostatic field.

137. For a triangular and sawtooth waveform the rms voltage or current equals

138. An inductive load always has a ​____ power factor

139. When the net reactance in a series coil-capacitor circuit is zero at frequency f, the nature of its reactance of frequency 2f is

140. In an ac wave, 30 degrees of phase is ___​ of a cycle.

141. In a multiple capacitor, the plate area is

142. Two capacitors of capacitance 9 µF and 18 µF in series will have a total capacitance of

143. In an ac circuit with XL and R in series, the

144. Kirchhoff’s laws (KCL and KVL) are applicable to

145. Which of the following is the peakiest?

146. When two coils of identical reactance are in parallel without mutual inductance, the reactance of the combination is ​____ the reactance of each coil.

147. What is the resonant frequency of a circuit when L of 3 microhenrys and C of 40 picofarads are in series?

148. An alloy composed of 84 % copper, 12 % manganese and 4 % nickel.

149. What can be used to estimate resonant frequency and to find reactance at any frequency for any value of capacitor or inductor?

150. In a series RLC circuit

151. A capacitor is used to

152. Which waveform in which the RMS value and the mean value are equal?

153. The voltage cannot be exactly in phase with the current in a circuit that contains

154. A factor that states how much the resistance changes for a change in temperature?

155. The ratio between the reactive power and the apparent power of an ac load is called

156. If the output resistance of a voltage source is 4​Ω​, it internal resistance should be

157. In an inductive coil, the rate of rise of current is maximum

158. In an ac circuit with inductive reactance, the

159. An inductance of 1 mH is

160. The ____ of an alternating quantity is defined as the fractional part of a period or cycle through which the quantity has advanced from selected origin.

161. A capacitive load always has a ____ ​ power factor

162. A rheostat is a form of

163. Which of the following does not affect resistance?

164. Which of the following has negative temperature coefficient?

165. Capacitance increase with

166. Form its definition, the unit of electric field,​ ​ is the N/C and equivalent unit of​ ​is the

167. What is the peak factor for alternating current or voltage varying sinusoidally?

168. The charging of a capacitor through a resistance obeys

169. Barium-strontium titanite dielectric material is also called

170. Transient period is considered over after

171. What is the form factor of a triangular wave?

172. Which of the following does not generally affect the value of a capacitor?

173. Why are inductance and capacitance not relevant in a dc circuit?

174. At parallel resonance, the currents flowing through L and C are

175. The capacitance of a capacitor is ​_____ relative permittivity.

176. “Any resistance R in a branch of a network in which a current I is flowing can be ​ replaced by a voltage equal to IR”. This states

177. The reason why electrical appliances are not connected in series.

178. For a series AC circuit, ​ _____​ is not used as a reference phasor.

179. In a complex number 5 + j 10, 10 is called _____​ part.

180. An inductive circuit of resistance 16.5​Ω ​and inductance of 0.14 H takes a current of 25 A. if the frequency is 50 Hz, find the supply voltage.

181. If a certain circuit has a current that is lagging the voltage by 45˚, then it displays

182. For maximum power transfer, what is the relation between load resistance RL and internal resistance R of the voltage source?

183. Which of the following is a disadvantage of a wire-wound resistor?

184. Which of the following represents the energy stored in a capacitor?

185. For a carbon composition resistor, typical resistance values range from

186. A three-by-three, series-parallel matrix of resistors, all having the same ohmic value, would have a net resistance of

187. What is the cross-sectional are of a conductor whose diameter is 0.001 inch?

188. Which of the following describes the action of a capacitor?

189. In liquids and gases, ionization current results from a flow of

190. The ​ ​ wavelength ​ of ​ an ​ ​ alternating ​ ​ waveform ​ depends upon the ____ of the variation.

191. What is the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?

192. A wire of one kilometre length has a resistance of 20​Ω​. If the length is halved, then the new resistance is ​____​ the original resistance.

193. The value of temperature coefficient (a) is dependent upon

194. When capacitors are connected in series, the total capacitance is

195. A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in series, the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.

196. Which of the following is not considered a physical factor affecting resistance?

197. What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?

198. What is the hot resistance of a 100 W, 220 V incandescent lamp?

199. As applied to a series RLC circuit, bandwidth means

200. When the temperature of copper wire is increased its resistance is

201. Property of an electric circuit that dissipates electric energy

202. The superposition theorem is used when the circuit contains

203. What is the time constant for L of 240 mH in series with R of 20​Ω​?

204. A 5 µF capacitor charge to 5V has a stored charge equal to

205. What is the reciprocal of capacitance?

206. What does a capacitor store?

207. What determines the magnitude of electric current?

208. The second strip of an electronic resistor color-code represents

209. The electric field strength between capacitor plates has a unit of

210. Series resonant circuit is sometimes known as

211. Loop currents should be assumed to flow in which direction

212. In a circuit, a passive element is one which

213. A circuit whose parameters change with voltage or current.

214. A gang capacitor is a variable capacitor in which capacitance is varied by changing the

215. The charging of a capacitor through a resistance follows what law?

216. If a coil has a Q of 10, it means that

217. What is the resonant frequency of a circuit when L of 25 microhenrys and C of 10 picofarads are in parallel?

218. If one resistance in a series connection is open, then

219. In a series RLC circuit

220. Tungsten filament of bulbs has a hot resistance higher than its cold resistance due to its temperature coefficient which is

221. Which statement is true about a passive circuit?

222. When two unequal values of resistors are connected in parallel across a dc source, greater current flows through the

223. What is the rms value of a square wave?

224. What rating of a resistor determines its ability to absorb heat?

225. The impedance in the study of electronics is represented by resistance and

226. The ratio of W/VA in an ac circuit means

227. The Q-factor of a series resonant circuit is also known as

228. If the inductance is decreased, the impedance of the circuit containing a resistor a capacitor and an inductor connected in series to an ac source

229. Which of the following capacitors is suitable for DC filter circuits?

230. With double the number of turns by the same length and area, the inductance is

231. When voltage is applied across a ceramic dielectric the electrostatic field produced is 50 times greater than air dielectric. The dielectric constant of ceramic therefore is

232. Metal tin becomes a superconductor at approximately

233. For a series circuit, the higher the quality factor

234. For greater accuracy, the value of phase angle​ should be determined from

235. The factor 0.707 for converting peak to RMS applies only to

236. The reason why alternating current can induce voltage is

237. Norton’s theorem is ____ Thevenin’s theorem.

238. For a parallel AC circuit, ____ is used as a reference phasor.

239. An intermittent and non-symmetrical alternating current like that obtained from the secondary winding of an induction coil

240. If a multiplate capacitor has 10 plates, each of area 10 cm2, then

241. For a linear circuit, ____ voltage or current is used to calculate average power.

242. In a circuit, an active element is one which

243. The maximum power transfer theorem is used in

244. Which of the following dielectric materials makes the highest-capacitance capacitor?

245. Which of the following dielectric materials makes the lowest-capacitance capacitor?

246. The unit of elastance is

247. What dielectric is generally employed by a variable capacitor?

248. Which of the following is a way of decreasing mutual inductance?

249. Permeability is otherwise known as

250. What is expected when two 20​KΩ​, 1 watt resistor in parallel are use instead of ​ one 10​KΩ​, 1 watt?

251. The power factor of a circuit is equal to

252. The result of rust in electrical (wire) connection is

253. When capacitors are connected in parallel, the total capacitance is

254. A series RL circuit has R of 10​Ω ​and XL of 5​Ω​, its impedance in rectangular form is given by

255. A capacitance of 0.05 µF equals

256. Thevenin’s theorem is what form of an equivalent circuit?

257. When current and voltage are in phase in an ac circuit, the ____​ is equal to zero.

258. When the power factor of a circuit is zero,

259. Which of the following is not a factor affecting the capacitance of a basic capacitor?

260. Delta to wye or wye to delta transformation technique is applied to a ___ network.

261. Refers to the outward-curving distortion of the lines of force near the edges of two parallel metal ​ plates that form a capacitor.

262. Voltage resonance means

263. Resistor with colored bands in the body

264. How many degrees of phase represent one full cycle?

265. Series resonance occurs when

266. The average value of a triangular or sawtooth wave is ___ times its peak value.

267. A series RLC circuit consists of a 10​Ω ​resistor in series with L = 10 µH, and C = 100 µF.

Determine a new value of I, for which the resonant frequency is one–half the original value.

268. What is the specific resistance of a pure silicon?

269. In a parallel bank with unequal branch resistances

270. The arc across a switch when it open an RL circuit is a result of the

271. The temperature coefficient of resistance of electrolytes is

272. What is the complex impedance of a circuit with an absolute resistance of 300​​Ω​​

273. If an emf in circuit A produces a current in circuit B, then the same emf in circuit ​ B produces the same current in circuit A. this theorem is known as

274. High resistance values are a consequence of the____ of the film.

275. In Norton’s theorem, the short circuit current is obtained by

276. Which of the following capacitors are used only in dc circuits?

277. The RMS value of a triangular or sawtooth waveform is ___​ times its peak value.

278. When resistance are connected in parallel, the total resistance is

279. Parallel resonant circuit is sometimes called as

280. If three 9 mH inductors are connected in parallel without mutual inductance then the total inductance is

281. Which of the following conditions is not true for a series RLC circuit at resonance?

282. In a rectangular wave, the form factor is

283. A neon glow lamp used as a night light ionizes at approximately

284. The farad is not equivalent to which of the following combination of units

285. According to Gauss theorem, flux can be equated to

286. Electron flow assumes charges flow from

287. The ​ open-circuit ​ voltage ​ at ​ the ​ terminal ​ of load ​ RL is 60V. ​Under the condition of maximum power transfer, the load voltage will be

288. The mutual inductance between two coils is ___ the reluctance of magnetic path.

289. The hot resistance of an incandescent lamp is about ___ times its cold resistance.

290. VL = VC in a series RLC circuit when

291. What value of R is needed with a 0.05 µF C for an RC time constant of 0.02 s?

292. Which of the following does not refer to electrical energy?

293. What increases the resistance of wire at high frequencies?

294. The power factor of a certain circuit in which the voltage lags behind the current is 80 %. To increase the power to 100 %, it is necessary to add ​___ ​ to the circuit.

295. In a pure capacitance,

296. Under the conditions of maximum power transfer, a voltage source is delivering a power of 15 W to the load. What is the power generated by the source?

297. The resistance of an insulator ___ when its temperature is increased.

298. For series capacitors, total charge is

299. In an ac circuit with a resistive branch and an inductive branch in parallel, the

300. A switch designed to have low capacitance between its terminal when open.