Choose the correct option for the following **Network theory assertion & reason questions**.

- Both A and R are true and R is a correct explanation of A
- Both A and R are true but R is not a correct explanation of A
- A is true but R is false
- A is false but R is true

Q. (A): The direction of flow of conventional current is taken opposite to that of electrons.

(R): Electrons have negative charge.

Q. (A): The hot resistance of the bulb’s filament is higher than its cold resistance.

(R): The resistivity of bulb’s filament is high.

Q. (A): Two wires of same length with different cross-sectional areas are connected in series. The heat produced by the current is more in the thicker wire.

(R): The thicker wire has low resistance.

Q. (A): The Kirchhoff’s current law states that the sum of current entering at any node is equal to the sum of currents lei that node.

(R): The Kirchhoff’s current law is based on the law of conservation of charge.

Q. (A): If Thevenin’s equivalent of a circuit is known, its Norton equivalent is also known.

(R): Norton’s equivalent is reciprocal of Thevenin’s equivalent.

Q. (A): Norton’s theorem is applied to a network for which no equivalent Thevenin’ s network exists.

(R): Norton’s theorem enables one to calculate quickly current and voltage in a particular branch of interest in a complicated network.

Q. (A): Node-voltage analysis of networks is a method that uses Kirchhoff’s current law to obtain a set of simultaneous equations that, when solved, will provide information concerning the magnitudes and phase angles of the voltages across each branch.

(R): The ideal generator maintains constant voltage amplitude and waveshape regardless of the amount of current it supplies to the circuit.

Q. (A): A network consisting of ‘n’ nodes and ‘e’ elements can be completely analysed from (e – n + 1) mesh equations or (n – 1) node equations.

(R): The number of mesh equations plus number of node equations is equal to the number of elements in the network.

Q. (A): All networks made up of passive, linear time invariant elements are reciprocal.

(R): Passivity and time invariance of elements do not guarantee reciprocity of the network.

Q. (A): A four terminal passive linear network will always have an equivalent T-network.

(R): The Thevenin’s theorem is applicable in cases of transfer functions also.

Q. (A): A driving-point function should have its poles and zeros to the left of s-plane.

(R): Only a positive real function can be realized in network form.