Virtual value or effective value of a.c. is
  • -0.637I0
  • -0.707I0
  • 0.637I0
  • 0.707I0
Given the instantaneous value of current from a.c. source is I = 8 sin 623t. Find the r.m.s value of current
  • 5.656 A
  • 8 A
  • 2.848 A
  • 1.414 A
What is time constant
  • characteristic time with which current grows and decays
  • the time current takes to reach the minimum value only
  • time for the complete cycle
  • the time current takes to reach the peak value only
Find the instantaneous voltage for an a.c. supply of 200V and 75 hertz
  • E = 282.8 sin 50πt
  • E = 282.8 sin 150πt
  • E = 282.8 sin 75πt
  • E = 282.8 sin 100πt
Which phasor represents the relationship between alternating current and alternating e.m.f. for a resistance?
16-300x208.jpg
  • B
  • A
  • Both A and B
  • Neither A nor B
Alternating current is represented by
138.png
  • A
  • B
  • C
  • D
What is the relationship between Em and E0
  • Em=-0.537 E0
  • Em=-0.737 E0
  • Em=-0.637 E0
  • Em=-0.707 E0
The only component that dissipates energy in ac circuit is:
  • Capacitor
  • Inductor
  • Resistors
  • None of these
Which is more dangerous?
  • 220 V a.c
  • 220 V d.c
  • Both 220 V a.c. and 220 V d.c
  • Both 220 V a.c. and 220 V d.c. are not dangerous
The average power dissipation in pure resistive circuit is:
139.png
  • A
  • B
  • C
  • D
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