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ECE :: Network Analysis and Synthesis

  1. A magnetic circuit has an iron length of 20 cm and air gap length 0.1 cm. If μr = 200 then

  2. A.
    mmf for iron and air gap are equal
    B.
    mmf for iron is much less than that for air gap
    C.
    mmf for iron is much more than that for air gap
    D.
    either (a) or (c)

  3. A circuit is fed by two sources of the same frequency and values 100 ∠0° V and 20 ∠30°V. The current in a particular branch is 5 ∠19° A. If the magnitudes of the sources and changed to 200 ∠0° V and 40 ∠30° V, the current in that branch should be

  4. A.
    5 ∠19° A
    B.
    10 ∠19° A
    C.
    10 ∠38° A
    D.
    10 ∠9.5° A

  5. Two coils X and Y have self inductances of 5 mH and 10 mH and mutual inductance of 3 mH. If the current in coils X change at a steady rate of 100 A/s, the emf induced in coil Y is

  6. A.
    0.3 V
    B.
    0.5 V
    C.
    1 V
    D.
    1.5 V

  7. Two capacitors of 2 μF and 4 μF capacitance are connected in series across a 30 V dc battery. After the capacitors have been charged, the voltage across them will be

  8. A.
    15 V each
    B.
    10 V and 20 V
    C.
    20 V and 10 V
    D.
    30 V each

  9. In the circuit shown in the figure, the current supplied by the sinusoidal current source I is

  10. A.
    28 A
    B.
    4 A
    C.
    20 A
    D.
    not determinable from the data given

  11. The frame of an electric motor is earthed through three earthing plates resistances 30 Ω, 20 Ω and 10 Ω respectively. During fault the energy dissipated by three plates are W1, W2 and W3. Then

  12. A.
    W1 > W2 > W3
    B.
    W1 < W2 < W3
    C.
    W1 = W2 = W3
    D.
    W1 + W3 < W2

  13. If figure, power dissipated in 30Ω resistance will be maximum when value of R =

  14. A.
    30 Ω
    B.
    16 Ω
    C.
    9 Ω
    D.
    zero

  15. In the following non-planar graph no.of independent loop equations are

  16. A.
    8
    B.
    12
    C.
    7
    D.
    5

  17. Two voltages are 50 ∠0 V and 75 ∠ - 60° V. The sum of these voltages is

  18. A.
    109 ∠ - 60° V
    B.
    109 ∠ - 25° V
    C.
    109 ∠ - 36.6° V
    D.
    100 ∠ - 50.1° V

  19. An RLC series circuit is fed form 100 V ac supply. Inductance is 1 H and Q = 7.5. At resonance, the voltage across inductance is

  20. A.
    750 V
    B.
    100 V
    C.
    about 13.5 V
    D.
    1500 V