Content Strategy Manager
Kirchhoff's Law are part of the Current Electricity chapter in Class 12 Physics syllabus. Kirchhoff's Laws are classified into Current law and Voltage law. Kirchhoff’s law is based on the law of conservation of charges.
Kirchhoff's Current Law: Total current entering the node of an electric circuit is equal to the total current leaving the circuit.
Kirchhoff’s Current Law
Kirchhoff's Voltage Law: Kirchhoff's voltage law states that the algebraic sum of the potential differences in any loop must be equal to zero.
Kirchhoff's Law Video Explanation
Read More: NCERT Solutions for Class 12 Chapter 3 Current Electricity
MCQs on Kirchhoff’s Law
Ques 1. KCL is based on the fact that
- There is a possibility for a node to store energy.
- There cannot be an accumulation of charge at a node.
- Charge accumulation is possible at node
- Charge accumulation may or may not be possible.
Click here for the answer
Answer: b
Explanation: As the node is not a circuit element, charge accumulation does not take place at the node.
Ques 2. Relation between currents according to KCL is
- i1=i2=i3=i4=i5
- i1+i4+i3=i5+i2
- i1-i5=i2-i13-i4
- i1+i5=i2+i3+i4
Click here for the answer
Answer: d
Explanation: As per Kirchhoff’s Current Law, entering currents=leaving currents.
Ques 3. The algebraic sum of voltages around any closed path in a network is equal to
- Infinity
- 1
- 0
- Negative polarity
Click here for the answer
Answer: c
Explanation: As per Kirchhoff’s Voltage Law, the sum of voltages around the closed path in a network is zero.
Ques 4. Calculate potential difference between x and y
- 4.275v
- – 4.275v
- 4.527v
- – 4.527v
Click here for the answer
Answer: b
Explanation: As per Kirchhoff’s law,
I1 = 3/3+5 = 3/8 = 0.375Ω
I2 = 4/5 = 0.8Ω
Vxy = vx – vy
Vx + 5I1 + 4 – 2I2 – vy = 0
Vx – vy = 2I2 – 4 – 5I1 = -4.275Ω
Ques 5. Find R-value from the below circuit?
- 17.5 Ω
- 17.2 Ω
- 17.4 Ω
- 17.8 Ω
Click here for the answer
Answer: a
Explanation: As per Kirchhoff’s voltage law,
70 – 5I – 7(I – 2) = 0
I = 7A
KVL to 2nd loop: 7(I – 2) – 2R = 0
R=17.5Ω
Ques 6. Determine currents I1 I2 and I3 from the given circuit.
- - 3.3A, -8.5A, 2.4A
- 3A, -8A, 2A
- 3.3A, 8.5A, -2.4A
- 3.2A, 8.6A, 2.3A
Click here for the answer
Answer: c
Explanation: I1 = I1 – I2 + 8 + I3 + 3
I2 – I3 = 11 -> 1
-11 I1 – 7(I1 – I2) = 0
-18 I1 + 7 I2 = 0 → 2
-11 I1 – 15 I3 =0 →3
Solving I1 = 3.32A I2 = 8.5A I3 = -2.4A
Ques 7. All _____________ are loops but _______________ are not meshes
- Loops, Meshes
- Meshes, loops
- Branches, loops
- Nodes, Branches
Click here for the answer
Ans. b
Explanation: A mesh cannot be subdivided into loops. Thus loops are not meshes in an electrical circuit.
Ques 8. Solve and find the value of I from the given electrical circuit.
- – 0.5A
- 0.5A
- – 0.2A
- 0.2A
Click here for the answer
Answer: a
Explanation: Veq = 10 + 5 -20 = -5u
Req = 5 + 2 + 3 = 10Ω
I = V/R = -5/10 = -0.5A
Ques 9. A junction where two (or) more network elements meet is known as?
- Node
- Branch
- Loop
- Mesh
Click here for the answer
Answer: a
Explanation: Node is a junction where two or more network elements meet.
Ques 10. Which of the following is the second step of incidence matrix of a directed graph?
- Choose a node
- Assign values to element and check for direction
- Repeat the previous steps
- All the above
Click here for the answer
Answer: b
Explanation: The second step of the incidence matrix of the directed graph is to assign values to elements and check for direction.
Ques 11. Which of the following represents that current is either entering or leaving the node in an electric circuit of an incident matrix?
- +1
- - 1
- 0
- Both a and b
Click here for the answer
Answer: c
Explanation: 0 indicates that the current entering the node of a circuit is equal to the current leaving the circuit.
Ques 12. Which of the following represents that current is entering the node in an electric circuit of an incident matrix?
- +1
- - 1
- 0
- Both a and b
Click here for the answer
Answer: a
Explanation: +1 indicates that the current is entering the node of a circuit.
Do Check Out:
Ques 13. Which of the following represents that current is leaving the node in an electric circuit of an incident matrix?
- +1
- -1
- 0
- Both a and b
Click here for the answer
Answer: b
Explanation: -1 indicates that the current is entering the node of a circuit.
Ques 14. Electrical representation of network graph is represented using______ types?
- 2
- 1
- 3
- 4
Click here for the answer
Answer: c
Explanation: Electrical representation of network graph is represented using 3 types namely, incident matrix, fundamental loop matrix and fundamental cut set matrix.
Ques 15. Kirchhoff’s law can also be represented using______?
- Maxwell equation
- Quantum equations
- Hall effect
- All the above
Click here for the answer
Answer: a
Explanation: Kirchhoff’s current and voltage law can also be represented using Maxwell’s equation.
Ques 16. Which of the following law is used with Kirchhoff’s Current Law?
- Ohms law
- Faraday law
- Coulomb’s law
- Both b and c
Click here for the answer
Answer: a
Explanation: Ohms law is used with Kirchhoff’s Current Law. Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Ques 17. Which of the following field is derived from Kirchhoff’s loop law/ voltage law?
- Electrical
- Magnetic
- Electrostatic
- Electromagnetic
Click here for the answer
Answer: c
Explanation: An electrostatic field derives Kirchhoff’s loop law.
Ques 18. Which of the following parameter is used for performing the analysis process?
- Current
- Voltage
- Resistance
- Both a and b
Click here for the answer
Answer: d
Explanation: Current and voltage are the parameters used. This is why Kirchhoff’s laws are used for network analysis.
Ques 19. Arrange the following steps in the order followed in nodal analysis.
- Apply KCL to each node
- Calculate branch currents
- Perform mathematical calculation and obtain voltage at node
- Assign an arbitrary value of voltage at each node in circuit
- 1,2,3,4
- 4,1,2,3
- 3,1,2,4
- 4,2,1,3
Click here for the answer
Answer: b
Explanation: The correct order of nodal analysis is:
- Assign an arbitrary value of the voltage at each node in the circuit.
- Apply KCL to each node.
- Calculate branch currents.
- Perform mathematical calculations and obtain voltage at the node.
Ques 20. Arrange the following steps in the order followed in Mesh analysis.
- Every loop is assigned with loop based current value
- Perform mathematical solvation to obtain loops currents value
- Kirchhoff’s KVL is implemented for every loop
- 1,2,3
- 3,2,1
- 1,3,2
- 3,1,2
Click here for the answer
Answer: c
Explanation: The correct order of mesh analysis is:
- Every loop is assigned with loop based current value
- Kirchhoff’s KVL is implemented for every loop
- Perform mathematical solvation to obtain loops currents value
Ques 21. KVL is performed using___?
- Nodal analysis
- Mesh analysis
- Both a and b
- Voltage analysis
Click here for the answer
Answer: b
Explanation: Kirchhoff’s voltage law is performed using mesh analysis as it takes into account the loops and meshes in the electrical circuit.
Ques 22. KCL is performed using___?
- Nodal analysis
- Mesh analysis
- Both a and b
- Voltage analysis
Click here for the answer
Answer: a
Explanation: Kirchhoff’s current law is performed using nodal analysis as the entire law is based on the current entering through the node and leaving the circuit.
Ques 23. Which of the formula defines KCL where i1, i2 are incoming currents and i3,i4 are outgoing currents from a node in a circuit?
- i1+i2=i3+i4
- i1+i3=i2+i4
- i1-i2=i3-i4
- i4-i1=i2+i3
Click here for the answer
Answer: a
Explanation: As per Kirchhoff’s current law, Incoming current is equal to outgoing current. Therefore the formula is i1+i2=i3+i4.
Ques 24. The equation Σe = ΣIR is applicable to which law?
- Kirchhoff’s current law
- Kirchhoff’s voltage law
- Kirchhoff’s third law
- Newton’s law
Click here for the answer
Answer: b
Explanation: This equation is on par with Ohm’s law where Voltage V = IR. Since it deals with voltage, we can easily conclude that this equation is related to Kirchhoff’s voltage law.
Ques 25. Find the false statement.
- Sum of voltage over any closed loop is zero.
- Kirchhoff’s law can be applied to any circuit regardless of its structure and composition.
- Kirchhoff’s second law is applied at nodes.
- Kirchhoff’s first law can be applied to both planar and non-planar circuits.
Click here for the answer
Answer: c
Explanation: Kirchhoff’s second law or voltage law is applied at loops. It is Kirchhoff’s current law that is applied at nodes.
Read More:
Comments