Question

Do both questions please. Thanks.

Which of the following statements about Kirchhoff's Current Law (KCL) below are true? ■ The sum of currents going into the node equals the sum of the currents leaving the node Currents going into the node are always assumed to have a positive sign ■ KCL is derived from conservation of electric charge (ie charge cannot build up at a node) KCL cannot be applied to a node connected to a voltage controlled current source G KCL describes the flow of mesh currents through a circuit ■ If possible KCL should be applied to a voltage source as it will reduce the number of unknowns in a O If there are N number of nodes in a circuit then N number of KCL equations are needed to complete D Question 2 Which of the follow statements about Kirchhoff's Voltage Law (KVL) below are true? ■ In a closed loop around the circuit the voltage drop should equal the voltage gain The circuit must be physically closed (not have an open circuit) to use KVL ■ If there are only two circuit elements in a loop then the voltages of those two elements are equal O In a closed loop around the circuit the voltage drop should be less than the voltage gairn ■ In a closed loop around the circuit the voltage drop should be greater than the voltage gain O It is possible to draw N number of loops then you can generate N independent KVL equations G KVL can only be used in a loop around the whole circuit /externalt

Answer 1

(i) True sum of currents into the node = Sum of currents leaving the node (ii) False It is not compulsory to always assume that current entering node are positive We may also assume that current entering node rightarrow -ve and current exciting node rightarrow +ve (iii) True KCL is based on concentration of charge (iv) False KCL is universally applicable to node (v) False Mesh analysis is based on ohm's Law and KVL (vi) True (vii) False For 'n' nodes, (n - 1) KCL equations needed (i) True (ii) False KVL can be applied to open circuit (iii) True (iv) False Under given condition, KVL law will be violated (v) False KVL law will be violated under such case (vi) False For 'N' loops, the number of KVL equation is (b - N + 1) where b rightarrow No. of branch N rightarrow No. of nodes (vii) False. KVL can be used in any closed loop of the circuit.