Electrical Engineering Mid - I, September - 2014

1.Identify passive element among the following
  • voltage source
  • current source
  • inductor
  • All the above
Answer: C
2.If the voltage across a given capacitor is increased, the amount of stored charge
  • increases
  • decreases
  • remains same
  • zero
Answer: A
3.If one of the resistors in a parallel circuit is removed, what happens to the total resistance?
  • decreases
  • increases
  • doubles
  • remains constant
Answer: B
4.In a pure inductor, the current lags voltage by
  • 300
  • 450
  • 00
  • 900
Answer: D
5.In a pure resistive circuit the p.f. is
  • unity
  • 0
  • 0.8
  • 0.7
Answer: A
6.When two sinusoidal quantities are in phase, the phase difference is
  • 90
  • 0
  • 180
  • 45
Answer: B
7.Under resonance condition
  • Xl = Xc
  • Xl > Xc
  • Xl < Xc
  • Xl + Xc = 0
Answer: A
8.The output of a dc generator is
  • ac square wave
  • ac sinusoidal wave
  • pulsating dc
  • pure dc
Answer: B
9.If the number of poles in a lap wound generator be doubled, then the generator emf will
  • double
  • half
  • constant
  • zero
Answer: C
10.The critical resistance of a dc generator refers to the resistance of.
  • load
  • brush
  • field
  • armature
Answer: C
11.The total inductance of a parallel combination of 100mH, 50mH and 10mH is _________.
Answer: 7.69mH
12.Three equal resistances are connected in star. The equivalent resistance in delta is ______.
Answer: 3R
13.According to Faraday’s law, the relation between emf and change in flux is __________.
Answer:
14.The type of instrument used to measure dc is _________.
Answer: PMMC
15.The deflection in MI type instrument is proportional to ____________ of current.
Answer: square
16.__________ instrument scale is linear.
Answer: MC
17.If the peak value of a quantity is 2√2, then its rms value is ________.
Answer: 2
18.Under resonance condition, f = _____________.
Answer:
19.The characteristic drawn between no load emf and field current is known as _____________.
Answer: magnetising current
20.___________ changes the alternating emf generated by the dc generator in its armature coil to dc.
Answer: commutator