Network Elements and the Concept of Circuit

Network Elements and the Concept of Circuit

Easy Questions

Network Theory

Network Elements and the Concept of Circuit
Network theory miscellaneous
  1. Consider the following network:

    Which one of the following is the differential equation of V in the above network?








  1. View Hint View Answer Discuss in Forum

    The given network

    Applying KCL we get,
    VG = iC

    or VG = C
    dv
    dt

    or C
    dv
    		– GV = 0
    dt

    Hence alternative (C) is the correct choice.

    Correct Option: C

    The given network

    Applying KCL we get,
    VG = iC

    or VG = C
    dv
    dt

    or C
    dv
    		– GV = 0
    dt

    Hence alternative (C) is the correct choice.

  1. Consider the following circuit:

    What is the current I in the above circuit?








  1. View Hint View Answer Discuss in Forum

    The given circuit

    Applying superposition theorem.
    Case 1: When 60V source is taken, the equivalent circuit of the given circuit becomes.

    Req = 10 + {20 || (10 + 20 || 10)}

    or Req = 10 + 20 ||
    50
    3

    or Req = 10 + 20 ×
    50
    3
    20 +
    50
    3

    =
    210
    		= Ω
    11

    Ieq =
    V
    		=
    60
    		=
    60 × 11
    		=
    22
    		A
    VReq210/112107

    Let the current in the branch AB be I1, then
    I1 = Iq ×
    20
    20 +
    50
    3


    or I1 =
    22
    		 ×
    3 × 20
    		=
    12
    		= = 1.71 A (A to B)
    71107

    Case 2: When 15 A source is taken, the equivalent circuit of the given circuit becomes.

    Let the current in the branch BA be I2.

    Where, R1 = (10||20+10)||20
    or R1 = 100/7 Ω
    IR1 = 15 ×
    4
    		=
    15 × 4
    4 + 6 + R14 + 6 + 100/7


    or IR1 =
    15 × 4 × 7
    		 = 2.47 A.
    170

    and
    I2 = IR1 ×
    20
    20 +
    50
    3


    or I2 =
    2.47 × 20 × 3
    		=1.34A (B→A)
    110

    Now, I = I1 – I2 = 1.71 – 1.34 = 0.37 A.

    Correct Option: C

    The given circuit

    Applying superposition theorem.
    Case 1: When 60V source is taken, the equivalent circuit of the given circuit becomes.

    Req = 10 + {20 || (10 + 20 || 10)}

    or Req = 10 + 20 ||
    50
    3

    or Req = 10 + 20 ×
    50
    3
    20 +
    50
    3

    =
    210
    		= Ω
    11

    Ieq =
    V
    		=
    60
    		=
    60 × 11
    		=
    22
    		A
    VReq210/112107

    Let the current in the branch AB be I1, then
    I1 = Iq ×
    20
    20 +
    50
    3


    or I1 =
    22
    		 ×
    3 × 20
    		=
    12
    		= = 1.71 A (A to B)
    71107

    Case 2: When 15 A source is taken, the equivalent circuit of the given circuit becomes.

    Let the current in the branch BA be I2.

    Where, R1 = (10||20+10)||20
    or R1 = 100/7 Ω
    IR1 = 15 ×
    4
    		=
    15 × 4
    4 + 6 + R14 + 6 + 100/7


    or IR1 =
    15 × 4 × 7
    		 = 2.47 A.
    170

    and
    I2 = IR1 ×
    20
    20 +
    50
    3


    or I2 =
    2.47 × 20 × 3
    		=1.34A (B→A)
    110

    Now, I = I1 – I2 = 1.71 – 1.34 = 0.37 A.

  1. Which one of the following statements is correct? In a four-branch parallel circuit, 50 mA current flows in each branch. If one of the branches opens, the currents in the other branches—








  1. View Hint View Answer Discuss in Forum

    Since voltage across the branches remains unaltered, therefore current in other branches are unaffected after one of the branch opens.

    Correct Option: C

    Since voltage across the branches remains unaltered, therefore current in other branches are unaffected after one of the branch opens.

  1. Consider the following waveform diagram:

    Which one of the following gives the correct description of the waveform shown in the above diagram?








  1. View Hint View Answer Discuss in Forum

    The given waveform

    f(t) = f1(t) + f2(t) + f3(t)
    Where,

    On combining the above three waveform, we get the required waveform i.e.
    f(t) = u(t) + u(t – 1) + (t – 2) u (t – 2)

    Correct Option: C

    The given waveform

    f(t) = f1(t) + f2(t) + f3(t)
    Where,

    On combining the above three waveform, we get the required waveform i.e.
    f(t) = u(t) + u(t – 1) + (t – 2) u (t – 2)