Electric circuits miscellaneous

Electric circuits miscellaneous

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Electric Circuits

Electric circuits miscellaneous
  1. A series RLC circuit consisting of R = 10 ohms, XL = 20 ohms and Xc = 20 ohms is connected across an ac supply of 100 V (rms). The magnitude and phase angle (with reference to supply voltage) of the voltage across the inductive coil are respectively








  1. View Hint View Answer Discuss in Forum

    Since reactance are cancelling each other, the circuit is purely resistive and the current is in phase with the applied voltage. The voltage across the inductor leads the current through it by 90° .
    Since I = 100 ∠0° / {10 + j (20 – 20) } = 10∠0° VL = jLωI = 20 × 10 ∠90 = 200 ∠90°

    Correct Option: D

    Since reactance are cancelling each other, the circuit is purely resistive and the current is in phase with the applied voltage. The voltage across the inductor leads the current through it by 90° .
    Since I = 100 ∠0° / {10 + j (20 – 20) } = 10∠0° VL = jLωI = 20 × 10 ∠90 = 200 ∠90°

  1. The resonant frequency of the given series circuit is









  1. View Hint View Answer Discuss in Forum

    Leq = L1 + L2 + 2M = 6 H
    At resonance,

    ωLeq =
    1
    ωC

    ⇒ ω =
    1
    		 =
    1
    √Leq.C√12

    f =
    1
    		 Hz
    4 π √3

    Correct Option: B

    Leq = L1 + L2 + 2M = 6 H
    At resonance,

    ωLeq =
    1
    ωC

    ⇒ ω =
    1
    		 =
    1
    √Leq.C√12

    f =
    1
    		 Hz
    4 π √3

  1. The impedance seen by the source in the circuit in the figure is given by









  1. View Hint View Answer Discuss in Forum

    Z'L = 10∠30°
    1
    		2
    4

    = (0.54 + j0.31)Ω
    Total impedance = (4.54 – j1.69)Ω

    Correct Option: C

    Z'L = 10∠30°
    1
    		2
    4

    = (0.54 + j0.31)Ω
    Total impedance = (4.54 – j1.69)Ω