a) true b) false Ans: (b)
a) Copper losses are half of the iron losses b) Copper losses are equal to iron losses c) Copper losses are negligible in comparison to iron losses d) Iron losses are zero Ans: (b)
a) full load × (iron loss)/(f.l.cu-loss) b) full load × ((iron loss)2)/(f.l.cu-loss) c)full load × √((iron loss)/(f.l.cu-loss)) d) full load × √((f.l.cu-loss)/(iron loss)) Ans: (c)
a) The primary of such transformers is energized for all twenty-four hours and core losses occur throughout the day whereas copper losses will occur only when secondary is supplying load b) Core losses are always more than copper losses c) Core losses may destroy the insulation d) Core losses will heat up the oil of the transformer rapidly Ans: (a)
a) true b)false Ans: (b)
a) The percentage impedance should be equal b) The transformers should be properly connected with regard in polarity c) The primary winding of the transformers should be suitable for the supply system voltage and frequency d) The voltage ratings of transformers of primary and secondary winding should be identical Ans: ()
a) Incorrect polarity will result in dead short-circuit b) The transformers will not share load in proportion to their KVA rating c) The power factors of two transformers will be different from the power factor of common load d) None of the above Ans: (a)
a) Parallel operation will not be possible b) Parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load c) Transformers will be over heated d) Power factors of both of the transformers will be same Ans: (b)
a) Delta-delta connection b) Star-star connection c)Star-delta connection d)Delta-star connection Ans: (b)
a) true b) false Ans: (a)
a) true b) false Ans: (a)
a) To accomplish three phase to three phase transformation only b) To accomplish three phase to two phase transformation only c) To accomplish three phase to three phase and three phase to two phase transformation d) None of the above Ans: (c)
a) 10% greater than teaser transformer b) 15% greater than teaser transformer c) 57.7% greater than teaser transformer d) 66.6% greater than teaser transformer Ans: (b)
a) true b) false Ans: (a)
a) K/√3 b) √(3/2K) c) 2K/√3 d) √(K/2) Ans: (c)
 Multiple Choice Question (MCQ) of Electronics page-17:241. Which of the following statement is true? a) The saturation voltage VCF of silicon transistor is more than germanium transistor. b) The saturation voltage VCE for germanium transistor is more than silicon transistor. c) The saturation voltage VCE for silicon transistor is same as that for germanium. d) The saturation voltage VCE for silicon transistor is lower than germanium transistor. |
Multiple Choice Question (MCQ) of Electronics page-16:226. Which of the following statement is correct? a) Inner electrons are always present in the semiconductor. b) Bound electrons are always present in the semiconductor. c) Free electrons are always present in the semiconductor. d) Inner and bound electrons are always present in the semiconductor. |
Multiple Choice Question (MCQ) of Electronics page-15:211. The materials whose electrical conductivity is usually less than 1 × 106 mho/m are a) Semiconductors b) Conductors c) Insulators d) Alloys |
Multiple Choice Question (MCQ) of Electronics page-14:196. In which of the following device the base resistors are not added in the package but added externally? a) UJT b) CUJT c) PUT d) None of the above |
Multiple Choice Question (MCQ) of Electronics page-13:181. The conduction in JEFT is always by the a) Majority carriers b) Minority carriers c) Holes d) Electrons e) Holes and electrons simultaneously |