a) Three-phase mercury arc rectifier b) Six-phase mercury arc rectifier c) twelve-phase mercury arc rectifier d) Single phase mercury arc rectifier Ans: (a)
a) The power factor will increase b) The power factor will decrease c) The magnetizing current of the rotor will increase d) The magnetizing current of the rotor will decrease e) The speed of the motor will decrease Ans: (d)
a) One slip rings b) two slip rings c) three slip rings d) zero slip rings Ans: (d)
a) motor will stop b) motor will run at its normal speed in the same direction as it was running c) the direction of rotation will reverse d) motor speed will increase Ans: (c)
a) a d.c. series motor b) a d.c. shunt motor c) a d.c. compound motor d) magnetic amplifier Ans: (c)
a) A b) B c) C d) D Ans: (b)
a) Tachometer b) Voltmeter c) Ammeter d) Galvanometer Ans: (a)
a) R2 (1/s – 1) b) R2 (1/s – 1) c) R2 (s – 1) d) 1/R2 (s – 1) Ans: (b)
Where R2 is the resistance of the rotor in terms of secondary and s is the slip of motor.
a) Will decrease b) Will increase c) Will not change d) Will reach nearly zero Ans: (b)
a) The yoke b) The pole shoe c) The armature d) The field Ans: (b)
a) The size of core will decrease b) Less copper will be used c) Core losses will decrease d) Voltage output will decrease Ans: (a)
a) Sinusoidal voltage b) Direct voltage c) Sinusoidal with even harmonics d) Sinusoidal with oil harmonics Ans: (a)
a) No magnetic field b) No magnetic unless the poles are far apart c) A strong magnetic field d) A magnetic field if the poles tough Ans: (c)
a) Induced poles opposite from the original poles b) Induced poles the same as the original field c) Two north poles d) An induced magnetic field but no induced pole Ans: (a)
a) Iron, steel, and nickel are magnetic materials. b) Copper, iron, steel, and air are magnetic materials. c) Paper, wood, and steel are magnetic materials. d) Iron is magnetic materials but steel is non-magnetic. Ans: (a)
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