Network Theory MCQ Quiz - Objective Question with Answer for Network Theory - Download Free PDF
Last updated on Jun 23, 2025
Latest Network Theory MCQ Objective Questions
Network Theory Question 1:
Find the odd one in terms of units.
Answer (Detailed Solution Below)
Network Theory Question 1 Detailed Solution
Concept:
To find the odd one in terms of units, we need to analyze the dimensional units of each expression involving:
- L (Inductance): unit is henry (H) →
- R (Resistance): unit is ohm (Ω) →
- C (Capacitance): unit is farad (F) →
Analyzing each option:
Units:
This has units of seconds (time).
Units:
This also has units of seconds (time).
Units:
This also has units of seconds (time).
Units:
This has units of 1/seconds (frequency).
Conclusion:
Options 1, 2, and 3 all have the same unit: seconds (s), meaning they represent time constants or durations.
Option 4 has units of 1/second (Hz), representing frequency — so it is dimensionally different.
Network Theory Question 2:
Match List 1 and List 2
List 1 | List 2 | ||
A | Resistance | D | M-1L-2T4I2 |
B | Inductance | E | ML2T-2I-2 |
C | Capacitance | F | ML2T-3I-2 |
Answer (Detailed Solution Below)
Network Theory Question 2 Detailed Solution
Concept:
Each electrical quantity has a standard dimensional formula derived using base physical quantities: Mass (M), Length (L), Time (T), and Current (I or A).
Step-by-step Matching:
1. Resistance (A):
From Ohm's law:
Voltage (V) has dimensions of
So,
2. Inductance (B):
From the formula:
So, using the Voltage dimension again:
3. Capacitance (C):
From:
Charge (Q) has dimension
So,
Final Matching:
- A (Resistance) → F
- B (Inductance) → E
- C (Capacitance) → D
Answer:
Option 3) {(A, F), (B, E), (C, D)}
Network Theory Question 3:
Norton equivalent current source and corresponding resistance for the given circuit are respectively
Answer (Detailed Solution Below)
Network Theory Question 3 Detailed Solution
Norton Equivalent Current Source and Resistance:
In electrical circuit analysis, the Norton equivalent of a network is a simplified representation that consists of a single current source (Norton current source, IN) in parallel with a single resistance (Norton resistance, RN). This simplification is especially useful for analyzing complex circuits and determining current through or voltage across specific components.
To calculate the Norton equivalent for a given circuit, the following steps are performed:
- Determine the Norton current (IN): This is the current through the terminals of the circuit when they are short-circuited.
- Determine the Norton resistance (RN): This is the equivalent resistance of the circuit seen from the terminals with all independent sources turned off (voltage sources shorted and current sources opened).
Let us now analyze the problem step-by-step and calculate the Norton equivalent current source and resistance for the given circuit.
Step 1: Norton Current (IN)
To find the Norton current, we need to short-circuit the output terminals of the given circuit and calculate the current through the short circuit. For the given problem, after performing the necessary circuit analysis (such as applying Ohm’s Law, Kirchhoff’s Voltage Law, or Kirchhoff’s Current Law), the value of the Norton current is found to be:
IN = 0.4 A
Step 2: Norton Resistance (RN)
The Norton resistance is determined by calculating the equivalent resistance of the circuit as seen from the output terminals with all independent sources turned off:
- Voltage sources: Replaced by short circuits.
- Current sources: Replaced by open circuits.
After simplifying the given circuit appropriately, the equivalent resistance is calculated to be:
RN = 10 Ω
Final Norton Equivalent:
The Norton equivalent circuit for the given circuit is:
- Norton current source (IN): 0.4 A
- Norton resistance (RN): 10 Ω
Thus, the correct answer is:
Option 1: 0.4 A, 10 Ω
Network Theory Question 4:
For a given passive linear network, the Thevenin equivalent circuit series resistance and Norton equivalent circuit parallel resistance are respectively RTH and RN. Which of the following is true
Answer (Detailed Solution Below)
Network Theory Question 4 Detailed Solution
Explanation:
Analysis of Thevenin and Norton Equivalent Circuits
Definition: Thevenin and Norton equivalent circuits are techniques used in electrical engineering to simplify complex networks into more manageable forms for analysis. Thevenin's theorem represents a network as an ideal voltage source (VTH) in series with a resistance (RTH), while Norton’s theorem represents the same network as an ideal current source (IN) in parallel with a resistance (RN).
Key Relationship:
The resistances RTH (Thevenin resistance) and RN (Norton resistance) are always equal in value:
RTH = RN
This equivalence arises because both Thevenin and Norton transformations describe the same electrical network, but in different forms. The resistance remains unchanged during the transformation, as it represents the inherent impedance of the circuit.
Correct Option Analysis:
The correct option is:
Option 4: RTH = RN
This option is correct because the Thevenin equivalent resistance (RTH) and Norton equivalent resistance (RN) of a given passive linear network are always equal. This fundamental relationship ensures consistency in circuit transformations and analysis.
Network Theory Question 5:
Two capacitors of 0.005 μF, 40 V and 0.02 μF, 100 V are connected in series. What is the effective capacitance of the series combination and the maximum DC voltage that can be applied across it?
Answer (Detailed Solution Below)
Network Theory Question 5 Detailed Solution
Concept:
When capacitors are connected in series, the total (effective) capacitance is given by:
The maximum voltage across the combination is limited by the capacitor which reaches its voltage rating first, considering how voltage divides in series based on inverse of capacitance.
Given:
- C1 = 0.005 µF = 5 nF, Vmax1 = 40 V
- C2 = 0.02 µF = 20 nF, Vmax2 = 100 V
Step 1: Effective Capacitance
Step 2: Maximum DC Voltage
In series, same charge appears across both capacitors. Let charge Q be the same:
Let V2 = x, then V1 = 4x ⇒ Total voltage Vtotal = V1 + V2 = 4x + x = 5x
Now, apply voltage limit for C1: V1 ≤ 40 V ⇒ 4x ≤ 40 ⇒ x ≤ 10 V
⇒ Total Vtotal = 5x = 50 V (Maximum allowable without exceeding capacitor voltage ratings)
Hence, the correct answer is option 2
Top Network Theory MCQ Objective Questions
A voltage source having some internal resistance delivers a 2A current when a 5Ω load is connected to it. When the load is 10Ω, then the current becomes 1.6A. Calculate the power transfer efficiency of the source for a 15Ω load.
Answer (Detailed Solution Below)
Network Theory Question 6 Detailed Solution
Download Solution PDFConcept
The power transfer efficiency is:
The current across any resistor is given by:
where, I = Current
V = Voltage
R = Resistance
Calculation
Let the voltage and internal resistance of the voltage source be V and R respectively.
Case 1: When the current of 2 A flows through 5 Ω resistance.
Case 2: When the current of 1.6 A flows through 10 Ω resistance.
Solving equations (i) and (ii), we get:
2(5+R)=1.6(10+R)
10 + 2R = 16 + 1.6R
0.4R = 6
R = 15Ω
Putting the value of R = 15Ω in equation (i):
V = 40 volts
Case 3: Current when the load is 15Ω
η = 50%
Additional Information Condition for Maximum Power Transfer Theorem:
When the value of internal resistance is equal to load resistance, then the power transferred is maximum.
Under such conditions, the efficiency is equal to 50%.
As shown in the figure, a 1Ω resistance is connected across a source that has a load line V + i = 100. The current through the resistance is
Answer (Detailed Solution Below)
Network Theory Question 7 Detailed Solution
Download Solution PDFConcept:
Thevenin's Theorem:
Any two terminal bilateral linear DC circuits can be replaced by an equivalent circuit consisting of a voltage source and a series resistor.
To find Voc: Calculate the open-circuit voltage across load terminals. This open-circuit voltage is called Thevenin’s voltage (Vth).
To find Isc: Short the load terminals and then calculate the current flowing through it.
To find Rth: Since there are Independent sources in the circuit, we can’t find Rth directly. We will calculate Rth using Voc and Isc and it is given by
Application:
Given: Load line equation = V + i = 100
To obtain open-circuit voltage (Vth) put i = 0 in load line equation
⇒ Vth = 100 V
To obtain short-circuit current (isc) put V = 0 in load line equation
⇒ isc = 100 A
So,
Equivalent circuit is
Current (i) = 100/2 = 50 A
Applying loop-law in the given circuit.
- V + i × R = 0
- V + I × 1 = 0
⇒ V = i
Given Load line equation is V + i = 100
Putting V = i
then i + i = 100
⇒ i = 50 A
Ohm’s law is applicable to
Answer (Detailed Solution Below)
Network Theory Question 8 Detailed Solution
Download Solution PDFOhm’s law: Ohm’s law states that at a constant temperature, the current through a conductor between two points is directly proportional to the voltage across the two points.
Voltage = Current × Resistance
V = I × R
V = voltage, I = current and R = resistance
The SI unit of resistance is ohms and is denoted by Ω.
It helps to calculate the power, efficiency, current, voltage, and resistance of an element of an electrical circuit.
Limitations of ohms law:
- Ohm’s law is not applicable to unilateral networks. Unilateral networks allow the current to flow in one direction. Such types of networks consist of elements like a diode, transistor, etc.
- Ohm’s law is also not applicable to non – linear elements. Non-linear elements are those which do not have current exactly proportional to the applied voltage that means the resistance value of those elements’ changes for different values of voltage and current. An example of a non-linear element is thyristor.
- Ohm’s law is also not applicable to vacuum tubes.
If an ideal voltage source and ideal current source are connected in series, the combination
Answer (Detailed Solution Below)
Network Theory Question 9 Detailed Solution
Download Solution PDFConcept:
Ideal voltage source: An ideal voltage source have zero internal resistance.
Practical voltage source: A practical voltage source consists of an ideal voltage source (VS) in series with internal resistance (RS) as follows.
An ideal voltage source and a practical voltage source can be represented as shown in the figure.
Ideal current source: An ideal current source has infinite resistance. Infinite resistance is equivalent to zero conductance. So, an ideal current source has zero conductance.
Practical current source: A practical current source is equivalent to an ideal current source in parallel with high resistance or low conductance.
Ideal and practical current sources are represented as shown in the below figure.
- When an ideal voltage source and an ideal current source in series, the combination has an ideal current sources property.
- Current in the circuit is independent of any element connected in series to it.
Explanation:
In a series circuit, the current flows through all the elements is the same. Thus, any element connected in series with an ideal current source is redundant and it is equivalent to an ideal current source only.
In a parallel circuit, the voltage across all the elements is the same. Thus, any element connected in parallel with an ideal voltage source is redundant and it is equivalent to an ideal voltage source only.
Three resistors of 6 Ω are connected in parallel. So, what will be the equivalent resistance?
Answer (Detailed Solution Below)
Network Theory Question 10 Detailed Solution
Download Solution PDFConcept:
When resistances are connected in parallel, the equivalent resistance is given by
When resistances are connected in series, the equivalent resistance is given by
Calculation:
Given that R1 = R2 = R3 = 6 Ω and all are connected in parallel.
⇒ Req = 2 Ω
Siemens is the S.I unit of _________.
Answer (Detailed Solution Below)
Network Theory Question 11 Detailed Solution
Download Solution PDF
Quantity |
SI unit |
Resistance |
Ohm |
Conductance |
Siemens |
Capacitance |
Farad |
Inductance |
Henry |
When capacitors are connected in series across DC voltage __________.
Answer (Detailed Solution Below)
Network Theory Question 12 Detailed Solution
Download Solution PDFWhen capacitors are connected in series across DC voltage:
- The charge of each capacitor is the same and the same current flows through each capacitor in the given time.
- The voltage across each capacitor is dependent on the capacitor value.
When capacitors are connected in parallel across DC voltage:
- The charge of each capacitor is different and the current flows through each capacitor in the given time are also different and depend on the value of the capacitor.
- The voltage across each capacitor is the same.
A network of resistors is connected to a 16 V battery with an internal resistance of 1 Ω, as shown in the figure. Compute the equivalent resistance of the network.
Answer (Detailed Solution Below)
Network Theory Question 13 Detailed Solution
Download Solution PDFThe circuit after removing the voltage source
The total resistance of the new circuit will be the equivalent resistance of the network.
Req = Rt = 3 + 2 + 2 = 7 Ω
The equivalent resistance of the network is 7 Ω.
Mistake PointsWhile finding the equivalent resistance of the network, don't consider the internal resistance of the voltage source. Please read the question carefully it is mentioned in the question as well.
The symbol shown here is:
Answer (Detailed Solution Below)
Network Theory Question 14 Detailed Solution
Download Solution PDFThere are two kinds of voltage or current sources:
Independent Source: It is an active element that provides a specified voltage or current that is completely independent of other circuit variables.
Dependent Source: It is an active element in which the source quantity is controlled by another voltage or current in the circuit.
Which of the following statements are true for KCL and KVL
(a) Valid for distributed parameters networks
(b) Valid for lumped parameters networks
(c) Valid for linear elements
(d) Valid for non-linear elements
Code:
Answer (Detailed Solution Below)
Network Theory Question 15 Detailed Solution
Download Solution PDFDistributed Network:
- If the network element such as resistance, capacitance, and inductance are not physically separated, then it is called a Distributed network.
- Distributed systems assume that the electrical properties R, L, C, etc. are distributed across the entire circuit.
- These systems are applicable for high (microwave) frequency applications.
Lumped Network:
- If the network element can be separated physically from each other, then they are called a lumped network.
- Lumped means a case similar to combining all the parameters and considering it as a single unit.
- Lumped systems are those systems in which electrical properties like R, L, C, etc. are assumed to be located on a small space of the circuit.
- These systems are applicable to low-frequency applications.
Kirchoff's Laws:
- Kirchhoff’s laws are used for voltage and current calculations in electrical circuits.
- These laws can be understood from the results of the Maxwell equations in the low-frequency limit.
- They are applicable for DC and AC circuits at low frequencies where the electromagnetic radiation wavelengths are very large when we compare with other circuits. So they are only applicable for lumped parameter networks.
Kirchhoff's current law (KCL) is applicable to networks that are:
- Unilateral or bilateral
- Active or passive
- Linear or non-linear
- Lumped network
KCL (Kirchoff Current Law): According to Kirchhoff’s current law (KCL), the algebraic sum of the electric currents meeting at a common point is zero.
Mathematically we can express this as:
Where in represents the nth current
M is the total number of currents meeting at a common node.
KCL is based on the law of conservation of charge.
Kirchhoff’s Voltage Law (KVL):
It states that the sum of the voltages or electrical potential differences in a closed network is zero.