Q. Inductance of a coil Varies

  • (A) directly as the cross-sectional area of magnetic core
  • (B) directly as square of number of turns
  • (C) directly as the permeability of the core
  • (D) all of the above
πŸ’¬ Discuss
βœ… Correct Answer: (D) all of the above

Q. A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to

  • (A) average voltage
  • (B) r.m.s. voltage
  • (C) peak voltage
  • (D) none of the above
πŸ’¬ Discuss
βœ… Correct Answer: (B) r.m.s. voltage

Q. A parallel AC. circuit in resonance will

  • (A) have a high voltage developed across each inductive and capacitive section
  • (B) have a high impedance
  • (C) act like a resistor of low value
  • (D) have current in each section equal to the line current
πŸ’¬ Discuss
βœ… Correct Answer: (B) have a high impedance

Q. A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to

  • (A) the capacitive reactance in ohms
  • (B) the current flowing in capacitor
  • (C) the size of the capacitor being quite big
  • (D) the statement is incorrect
πŸ’¬ Discuss
βœ… Correct Answer: (D) the statement is incorrect

Q. A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be attributed to

  • (A) the big size of the inductor
  • (B) the reactance of the inductor
  • (C) the current flowing in the inductor
  • (D) the statement given is false
πŸ’¬ Discuss
βœ… Correct Answer: (D) the statement given is false

Q. A sine wave has a frequency of 50 Hz. Its angular frequency is _________ radian/second.

  • (A) 100 n
  • (B) 50 jt
  • (C) 25 JT
  • (D) 5 n
πŸ’¬ Discuss
βœ… Correct Answer: (A) 100 n

Q. All definitions of power factor of a series R-L-C circuit are correct except

  • (A) ratio of net reactance and impedance
  • (B) ratio of kW and kVA
  • (C) ratio of J and Z
  • (D) ratio of W and VA
πŸ’¬ Discuss
βœ… Correct Answer: (A) ratio of net reactance and impedance

Q. All the rules and laws of D.C. circuit also apply to A.C. circuit containing

  • (A) capacitance only
  • (B) inductance only
  • (C) resistance only
  • (D) All of the above
πŸ’¬ Discuss
βœ… Correct Answer: (C) resistance only

Q. An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms,

  • (A) the current through the resistance is more
  • (B) the current through the resistance is less
  • (C) both resistance and inductance carry equal currents
  • (D) none of the above
πŸ’¬ Discuss
βœ… Correct Answer: (C) both resistance and inductance carry equal currents

Q. Aphasoris

  • (A) a line which represents the magnitude and phase of an alternating quantity
  • (B) a line representing the magnitude and direction of an alternating quantity
  • (C) a coloured tag or band for distinction between different phases of a 3-phase supply
  • (D) an instrument used for measuring phases of an unbalanced 3-phase load
πŸ’¬ Discuss
βœ… Correct Answer: (A) a line which represents the magnitude and phase of an alternating quantity

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