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. In the circuit shown in figure, the switch S is closed at time t = 0. The voltage across the inductance at t = 0+, is—










  1. View Hint View Answer Discuss in Forum

    The given circuit
    at t = 0+ capacitor is replaced by short circuit and inductor is replaced by open circuit. The given circuit can be redrawn as

    Now, VL (0+) =
    2 × 10
    		 = 4V
    2 + 3

    Hence alternative (B) is the correct choice.


    Correct Option: B

    The given circuit
    at t = 0+ capacitor is replaced by short circuit and inductor is replaced by open circuit. The given circuit can be redrawn as

    Now, VL (0+) =
    2 × 10
    		 = 4V
    2 + 3

    Hence alternative (B) is the correct choice.


  1. The initial current in the circuit shown below when the switch is opened for t > 0—










  1. View Hint View Answer Discuss in Forum

    So in steady state when switch closed current 0 Amp.
    ∵ at initially capacitor is uncharged and there is no current flow due to open switch.


    Correct Option: B

    So in steady state when switch closed current 0 Amp.
    ∵ at initially capacitor is uncharged and there is no current flow due to open switch.


  1. The initial current in the circuit shown below when the switch is opened for t > 0 is—










  1. View Hint View Answer Discuss in Forum

    Applying KVL in the loop
    20 – 10I – 2I = 0
    at t < 0 20 = 12I
    or I = 1·67 A


    Correct Option: A

    Applying KVL in the loop
    20 – 10I – 2I = 0
    at t < 0 20 = 12I
    or I = 1·67 A


  1. The circuit shown below is under steady-state condition with the switch closed. The switch is opened at t = 0. What is the time constant of the circuit—










  1. View Hint View Answer Discuss in Forum

    As we know that τ =
    L
    		 =
    2
    Req10

    or τ = 0·2 S


    Correct Option: B

    As we know that τ =
    L
    		 =
    2
    Req10

    or τ = 0·2 S


  1. For the network shown below, the switch S is closed at t = 0 with the capacitor uncharged. The value of di(t) / dt at t = 0+ will be—










  1. View Hint View Answer Discuss in Forum

    When capacitor opened
    at t = 0+

    IC(0–) =
    V
    		 =
    .1000
    R100

    = 0.1 Amp
    at t = o+
    ⇒ 100 = 1000 IC + 1 / C ∫ICdt
    After differentiating, we get
    0 = 1000
    dIC
    		 +
    1
    		lc
    dtC

    Capacitor in short circuited
    -1000
    dIC
    		 =
    Ic
    		=
    .1
    dtC1 × 10 -6

    dI(+)
    		 =
    		-
    .1 × 10 +6
    dt103

    = – 100 Ampere.
    Hence alternative (B) is the correct choice.


    Correct Option: B

    When capacitor opened
    at t = 0+

    IC(0–) =
    V
    		 =
    .1000
    R100

    = 0.1 Amp
    at t = o+
    ⇒ 100 = 1000 IC + 1 / C ∫ICdt
    After differentiating, we get
    0 = 1000
    dIC
    		 +
    1
    		lc
    dtC

    Capacitor in short circuited
    -1000
    dIC
    		 =
    Ic
    		=
    .1
    dtC1 × 10 -6

    dI(+)
    		 =
    		-
    .1 × 10 +6
    dt103

    = – 100 Ampere.
    Hence alternative (B) is the correct choice.