Electric Current Questions and Answers for Viva

Answer-1: Electric current is define as the amount of charge flowing across an area held normal to the direction of flow of charge per unit time.

Answer-2: Nodal analysis is a method used to analyze electric circuits by examining the voltage at various nodes within the circuit.

Answer-3: Charges in motion constitutes an electric current.

Answer-4: A node is a point in an electric circuit where two or more circuit elements are connected together.

Answer-5: The SI unit of current is ampere (A).

Answer-6: KCL states that the algebraic sum of currents entering and exiting a node is zero. In nodal analysis, KCL is used to write equations for each node based on the currents flowing into and out of it.

Answer-7: Electric current is a scalar quantity.

Answer-8: One node is taken as reference node so, the number of equations we get is always one less than the number of nodes in the circuit, hence for 10 nodes we get 9 equations.

Answer-9: The direction of conventional current in an electric circuit tells the direction of flow of positive charges in that circuit.

Answer-10: A supernode is formed when a voltage source is connected between two nodes. It simplifies nodal analysis by treating the voltage source and the nodes it connects as a single entity.

Answer-11: A current whose magnitude does not change with time is called steady current.

Answer-12: The fundamental principle behind nodal analysis is the conservation of charge, as expressed by Kirchhoff's Current Law (KCL).

Answer-13: A current whose magnitude changes with time is called varying current.

Answer-14: The steps involve selecting reference node, applying KCL at each non-reference node, and solving the resulting system of equations.

Answer-15: If one coulomb of charge crosses an area normally in one second, then the current through that area is one ampere.

i.e. 1 ampere = 1 coulomb / 1 second   or   1 A = 1C s^-1

Answer-16: A floating node is a node that is not connected to any voltage or current source. It requires an additional equation to solve for its voltage.

Answer-17: Yes, nodal analysis can be extended to AC circuits by representing complex impedances as conductances in the nodal equations.

Answer-18: The steps involve selecting reference node, applying KCL at each non-reference node, and solving the resulting system of equations.

Answer-19: Voltage sources are treated as known values in nodal analysis. Their voltages are specified, and they are typically connected between a node and the reference node.

Answer-20: Nodal analysis is advantageous when dealing with circuits containing voltage sources or when the goal is to find node voltages directly.

Answer-21: Nodal analysis solutions can be verified by ensuring that the calculated node voltages satisfy KCL at each node and that the voltages across circuit elements are consistent with their respective current-voltage characteristics.

Answer-22: Dependent sources are treated like any other source in nodal analysis. The only difference is that their values depend on some other voltage or current in the circuit.

Answer-23: Nodal analysis is particularly useful when analyzing circuits with multiple current sources or when the goal is to find node voltages.

Answer-24: Choosing a reference node simplifies the analysis by allowing us to define all node voltages with respect to a common reference point, typically chosen as ground.

Answer-25: Yes, nodal analysis can be applied to circuits containing only voltage sources by incorporating a "dummy" current source to represent the voltage source.