Home / ECE / Network Analysis and Synthesis :: Section 5

ECE :: Network Analysis and Synthesis

  1. In an RL series circuit the inductance is 1H and current at an instant is 0.6 A. The energy stored in magnetic field is

  2. A.
    0.36 J
    B.
    0.18 J
    C.
    0.09 J
    D.
    0.03 J

  3. In a series ac circuit a voltage of 20 V at 25 Hz causes a current of 0.20 A, while the same voltage at 75 Hz causes a current of 0.12 A. The circuit consists of

  4. A.
    R and C in parallel
    B.
    R and C in series
    C.
    R and L in series
    D.
    either (a) or (b)

  5. Elements R, L, C are connected in parallel and excited by a dc current I. If iR, iL and iC are the currents through R, L, C respectively then at t = 0

  6. A.
    iR > iL > iC
    B.
    iL > iR > iC
    C.
    iC = 0
    D.
    iC = I

  7. In a practical voltage source, the terminal voltage

  8. A.
    cannot be less than source voltage
    B.
    cannot be higher than source voltage
    C.
    is always less than source voltage
    D.
    is always equal to source voltage

  9. When slider of the potentiometer AB is in the position shown in figure, what resistance reading would be indicated by an ohmmeter connected between A and C?

  10. A.
    zero
    B.
    infinite
    C.
    can't say
    D.
    none of the above

  11. A series R-L circuit has R = 1 Ω and L = 1 H. It is excited by a V battery at t = 0. The steady state condition is reached at

  12. A.
    t = 1 s
    B.
    t = 0.1 s
    C.
    t = 0 s
    D.
    t = ∞

  13. The current source in figure, can be replaced by

  14. A.
    a voltage source of 20 V in series with 5 ohm resistance
    B.
    a voltage source of 16 V in series with 4 ohm resistance
    C.
    a voltage source of 20 V in series with 4 Ω resistance
    D.
    a voltage source of 16 V in series with 5 Ω resistance

  15. In a purely inductive circuit, the current __________ the voltage by __________ .

  16. A.
    lags, 0°
    B.
    leads, 90°
    C.
    lags, 90°
    D.
    lags, 45°

  17. In the circuit of figure the voltage across C at t = 0+ is

  18. A.
    0 V
    B.
    20 V
    C.
    very large
    D.
    7.5 V

  19. The frame of electric motor is connected to three plates having earthing resistance of 10 Ω, 20 Ω and 30 Ω respectively. The materials of the three plates are copper, aluminium and iron respectively. The percentage of energy dissipated by 10 Ω earthing plate

  20. A.
    is more than 50% of total energy
    B.
    is less than 50% of total energy
    C.
    depends on the materials of the three plates
    D.
    may be more or less than 50% of total energy