Network Analysis Questions and Answers for Viva

Answer-1: Network analysis is a process through which we calculate various electrical parameters of a circuit element connected in an electrical network. It uses mathematical tools to analyze a circuit.

Answer-2: A device with two or more terminals into which the current may or may not flow.

Answer-3: A point at which terminals of more than two components are joined.

Answer-4: A component joining two nodes.

Answer-5: A group of branches within a network joined so as to form a complete loop such that there is no other loop inside it.

Answer-6: Two terminals where the current into one is identical to the current out of the other.

Answer-7: The main components of an electrical circuit are a conductive path, a source of electric power, and a load that requires electric power to function.

Answer-8: Parallel circuits, series circuits, and parallel-series circuits are the main types of circuits.

Answer-9: Resistors, capacitors, and inductors are the main elements used in an electrical circuit.

Answer-10: Resistance can be defined as the property of a conductor that opposes the flow of electric current. It is also defined as the voltage applied divided by the current flowing through it.

Answer-11: Ohm’s Law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.

Answer-12: A capacitor is a device that stores an electric charge and is made up of one or more pairs of conductors separated by an insulator.

Answer-13: The property of coil due to which it opposes any increase or decrease of current or flux through it is called self-inductance.

Answer-14: Mutual-inductance is the property of two coil because of which each opposes any change in the current flowing through the other by developing an induced emf.

Answer-15: A network in which physically separate resistors, capacitors and inductors can be represented.

Answer-16: A network in which resistors, capacitors and inductors cannot be electrically separable and isolated as individual elements. A transmission line has distributed resistor, inductor and capacitor which are not isolated from the network.

Answer-17: A unilateral network is one whose elements follow different laws relating to voltage and current for different direction of voltage and current polarities. For example, vacuum tubes, crystal and metal rectifiers are unilateral elements.

Answer-18: A bilateral network is defined as those whose elements can transmit well in either direction. For example, elements made of high conductivity material like iron core conductor is bilateral elements.

Answer-19: A linear network is one for which the principle of superposition holds. A circuit element is linear if the relation between voltage and current involves a constant coefficient. Therefore, it is concluded that a linear network must be bilateral but a bilateral network is not necessarily linear. For example, an iron core conductor is bilateral but it is non linear.

Answer-20: A generator which maintains its output current independent of the voltage across its terminals. It is indicated by a circle enclosing an arrow for reference current direction. An ideal current source has infinite internal resistance.

Answer-21: A generator which maintains its value of potential independent of the output current. An AC source is indicated by a circle enclosing a wavy line. An ideal voltage source has zero internal resistance.

Answer-22: A network containing circuit elements without any energy source is called as passive network.

Answer-23: A network containing energy source together with other circuit elements is called active network.

Answer-24: It is based on conservation of charge. It states that, “The algebraic sum of currents at any node of a circuit is zero”.

Answer-25: It is based on conservation of energy. It states that, “The algebraic sum of voltages in any closed path of network that is traversed in any single direction is zero”.

Answer-26: This theorem states that a linear, bilateral network consisting of active and passive elements can be replaced by a voltage source connected in series with impedance. The value of voltage source is equal to the open circuited voltage seen across the terminals and the impedance is equal to the impedance seen across the open circuited terminals with all sources replaced by their internal impedances.

Answer-27: This theorem states that the voltage across or current through any element due to multiple sources present in a linear network is equal to the algebraic sum of voltage across or current through that element due to individual source with all other sources replaced by their internal impedances.

Answer-28: It states that for any given time, the sum and power delivered to each branch of any electric network is zero. In other words, the summation of instantaneous power or summation of complex power of sinusoidal sources in a electrical network is zero.

Answer-29: This theorem states that the current in branch X due to voltage source in branch Y of a linear bilateral network is same as the current in branch Y when the same voltage source is connected in branch X of the network.

Answer-30: It states that, any two terminals of a network containing linear passive and active elements may be replaced by an equivalent current source IN in parallel with a resistance RN where IN is the current flowing through a short circuit placed across the terminals and RN is the equivalent resistance of the network as seen from the two terminals with all the independent sources suppressed.

Answer-31: This theorem states that, any number of current sources in parallel may be replaced by a single current source, whose current is the algebraic sum of individual source currents and source resistance is the parallel combination of individual source resistance.

Answer-32: Resonance is the condition when the voltage across a circuit becomes in phase with the current supplied to the circuit. At resonance, the circuit behaves like a resistive circuit.

Answer-33: It is the cosine of the angle between the voltage and current in any AC circuit. For a resistive circuit power factor is unity. For a capacitive circuit power factor is leading (i.e. current leads the voltage) and for an inductive circuit power factor is lagging (i.e. current lags the voltage).