The PYQ practice room
GATE EE 2016 Set 1
All 65 solved GATE EE 2016 Set 1 questions in exam order. Open a question, commit to an answer, and learn from the step-by-step solution. One question at a time.
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65
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100
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General Aptitude (GA)
101
Q1MCQ1 markEasyThe man who is now Municipal Commissioner worked as ____________________.Think it through. Then check your answer.Question
The man who is now Municipal Commissioner worked as ____________________.Correct answer
(B) a security guard at the university
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The sentence requires the use of appropriate articles. When referring to a profession in a general sense after 'worked as', the indefinite article 'a' is typically used (e.g., 'worked as a teacher'). 'The university' is used to refer to a specific institution known in the context. Therefore, 'a security guard at the university' is the most grammatically appropriate choice.2
Q2MCQ1 markEasyNobody knows how the Indian cricket team is going to cope with the difficult and seamer-friendly wickets in Australia. Choose the option which is closest in meaning to the…Think it through. Then check your answer.Question
Nobody knows how the Indian cricket team is going to cope with the difficult and seamer-friendly wickets in Australia.Choose the option which is closest in meaning to the underlined phrase in the above sentence.Correct answer
(A) put up with
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The phrasal verb 'cope with' means to deal effectively with something difficult or to endure a challenging situation. Among the options:
(A) put up with means to tolerate or endure something unpleasant, which is the closest synonym in this context.
(B) 'put in with' is not a standard idiomatic expression in this context.
(C) 'put down to' means to attribute something to a particular cause.
(D) 'put up against' means to make someone or something compete with or face another.3
Q3MCQ1 markEasyFind the odd one in the following group of words. mock, deride, praise, jeerThink it through. Then check your answer.Question
Find the odd one in the following group of words.mock, deride, praise, jeerCorrect answer
(C) praise
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The words 'mock', 'deride', and 'jeer' are synonyms that mean to ridicule, tease, or laugh at someone in a contemptuous manner. 'Praise', on the other hand, means to express warm approval or admiration of someone or something. Therefore, 'praise' is the odd one out as it is an antonym to the other three words.4
Q4MCQ1 markEasyPick the odd one from the following options.Think it through. Then check your answer.Question
Pick the odd one from the following options.Correct answer
(D) ONPMQ
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Let's analyze the pattern of the letters in each option relative to their alphabetical order.For each option, identify the set of 5 consecutive letters and then determine the order in which they appear.(A) CADBE:
Sorted letters: A, B, C, D, E
Positions in the given sequence relative to sorted: C (3rd), A (1st), D (4th), B (2nd), E (5th)
Pattern: 3, 1, 4, 2, 5(B) JHKIL:
Sorted letters: H, I, J, K, L
Positions in the given sequence relative to sorted: J (3rd), H (1st), K (4th), I (2nd), L (5th)
Pattern: 3, 1, 4, 2, 5(C) XVYWZ:
Sorted letters: V, W, X, Y, Z
Positions in the given sequence relative to sorted: X (3rd), V (1st), Y (4th), W (2nd), Z (5th)
Pattern: 3, 1, 4, 2, 5(D) ONPMQ:
Sorted letters: M, N, O, P, Q
Positions in the given sequence relative to sorted: O (3rd), N (2nd), P (4th), M (1st), Q (5th)
Pattern: 3, 2, 4, 1, 5Options (A), (B), and (C) follow the same pattern (3, 1, 4, 2, 5). Option (D) follows a different pattern (3, 2, 4, 1, 5). Therefore, (D) is the odd one out.The final answer is5
Q5MCQ1 markEasyIn a quadratic function, the value of the product of the roots (, ) is 4. Find the value ofThink it through. Then check your answer.Question
In a quadratic function, the value of the product of the roots (, ) is 4. Find the value ofCorrect answer
(B) 4ⁿ
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Given that the product of the roots of a quadratic function is .
We need to find the value of the expression .Let's simplify the denominator:
To add these fractions, we find a common denominator, which is :
Now, substitute this back into the original expression:
When dividing by a fraction, we multiply by its reciprocal:
Assuming , we can cancel out the term from the numerator and the denominator:
This can be written as .We are given that .
So, the value of the expression is .The final answer is6
Q6MCQ2 marksEasyAmong 150 faculty members in an institute, 55 are connected with each other through Facebook® and 85 are connected through WhatsApp®. 30 faculty members do not have Facebook® or…Think it through. Then check your answer.Question
Among 150 faculty members in an institute, 55 are connected with each other through Facebook® and 85 are connected through WhatsApp®. 30 faculty members do not have Facebook® or WhatsApp® accounts. The number of faculty members connected only through Facebook® accounts isCorrect answer
(A) 35
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Let be the total number of faculty members, .
Let be the set of faculty members with Facebook accounts. Given .
Let be the set of faculty members with WhatsApp accounts. Given .We are given that 30 faculty members do not have Facebook® or WhatsApp® accounts. This means they are neither in nor in .The number of faculty members who have at least one account (Facebook or WhatsApp or both) is:
.Using the Principle of Inclusion-Exclusion for two sets:
Substitute the known values:
Now, solve for , which represents the number of faculty members who have both Facebook and WhatsApp accounts:
.The question asks for the number of faculty members connected only through Facebook accounts.
This can be calculated as the total number of Facebook users minus those who also use WhatsApp:
.Thus, 35 faculty members are connected only through Facebook accounts.The final answer is7
Q7MCQ2 marksEasyComputers were invented for performing only high-end useful computations. However, it is no understatement that they have taken over our world today. The internet, for example, is…Think it through. Then check your answer.Question
Computers were invented for performing only high-end useful computations. However, it is no understatement that they have taken over our world today. The internet, for example, is ubiquitous. Many believe that the internet itself is an unintended consequence of the original invention. With the advent of mobile computing on our phones, a whole new dimension is now enabled. One is left wondering if all these developments are good or, more importantly, required.Which of the statement(s) below is/are logically valid and can be inferred from the above paragraph?(i) The author believes that computers are not good for us.
(ii) Mobile computers and the internet are both intended inventionsCorrect answer
(D) neither (i) nor (ii)
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Statement (i) is not logically valid because the author states they are 'left wondering' if the developments are good, which does not imply a firm belief that they are 'not good'. Statement (ii) is not logically valid because the text explicitly mentions that 'Many believe that the internet itself is an unintended consequence of the original invention', which contradicts the idea that it was an 'intended invention'. Therefore, neither statement can be inferred.8
Q8MCQ2 marksEasyAll hill-stations have a lake. Ooty has two lakes. Which of the statement(s) below is/are logically valid and can be inferred from the above sentences? (i) Ooty is not a…Think it through. Then check your answer.Question
All hill-stations have a lake. Ooty has two lakes.Which of the statement(s) below is/are logically valid and can be inferred from the above sentences?(i) Ooty is not a hill-station.
(ii) No hill-station can have more than one lake.Correct answer
(D) neither (i) nor (ii)
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The statement 'All hill-stations have a lake' means that being a hill-station is a sufficient condition for having at least one lake. (i) Ooty having two lakes does not prevent it from being a hill-station, so we cannot infer it is not one. (ii) The premise does not state that a hill-station can have only one lake; it just says they have 'a lake' (at least one). Thus, neither statement is a valid inference.9
Q9MCQ2 marksEasyIn a rectangle grid shown below, each cell is a rectangle. How many rectangles can be observed in the grid? [figure]Think it through. Then check your answer.Question
In a rectangle grid shown below, each cell is a rectangle. How many rectangles can be observed in the grid?
Correct answer
(C) 30
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A rectangle in a grid is formed by choosing two horizontal lines and two vertical lines. In a grid, there are horizontal lines and vertical lines. The number of ways to choose 2 horizontal lines is . The number of ways to choose 2 vertical lines is . Total number of rectangles = .10
Q10MCQ2 marksEasyChoose the correct expression for given in the graph. [figure]Think it through. Then check your answer.Question
Choose the correct expression for given in the graph.
Correct answer
(C) f(x) = 2 - x - 1
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The graph represents an absolute value function of the form , where is the vertex of the graph. From the given graph, the vertex is at . Thus, and . The expression becomes . To find the value of , we can use another point on the graph, such as . Substituting and into the equation: . Therefore, the expression is . This matches option (C).
Electrical Engineering
5511
Q11NAT1 markMediumThe maximum value attained by the function in the interval is _____.Think it through. Then check your answer.Question
The maximum value attained by the function in the interval is _____.Correct answer
0 to 0
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The function is . In the interval , is positive (), is non-negative (), and is non-positive (). Therefore, the product for all . The function attains its maximum value of 0 at the endpoints and .12
Q12NAT1 markEasyConsider a matrix with every element being equal to 1. Its only non-zero eigenvalue is ____.Think it through. Then check your answer.Question
Consider a matrix with every element being equal to 1. Its only non-zero eigenvalue is ____.Correct answer
3 to 3
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For an matrix where every element is 1, the rank of the matrix is 1. This implies that there is only one non-zero eigenvalue. The sum of the eigenvalues of a matrix is equal to its trace (the sum of the diagonal elements). For a matrix of all 1s, the trace is . Since all other eigenvalues are zero, the only non-zero eigenvalue must be 3.13
Q13MCQ1 markEasyThe Laplace Transform of isThink it through. Then check your answer.Question
The Laplace Transform of isCorrect answer
(A) (5)/(s² - 4s + 29)
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The Laplace transform of is given by . For , we have:Using the frequency shifting property of the Laplace transform, . Here , so:This matches option (A).14
Q14MCQ1 markMediumA function , such that and , is a solution of the differential equation . Then isThink it through. Then check your answer.Question
A function , such that and , is a solution of the differential equation . Then isCorrect answer
(B) 5e⁻²
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The given differential equation is .
The characteristic equation is , which gives , so .
The general solution is .
Using the boundary conditions:1..2..Thus, the specific solution is .
To find :
.15
Q15MCQ1 markMediumThe value of the integral over the contour , taken in the anti-clockwise direction, would beThink it through. Then check your answer.Question
The value of the integral over the contour , taken in the anti-clockwise direction, would beCorrect answer
(B) (48π i)/(13)
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Let .
The poles of are at and .
The contour is .- (Inside the contour)
- (Outside the contour)
.
Integral .16
Q16MCQ1 markEasyThe transfer function of a system is . The steady state output is for the input . The values of and…Think it through. Then check your answer.Question
The transfer function of a system is . The steady state output is for the input . The values of and , respectively areCorrect answer
(B) 1√(2), +45^
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The transfer function is .
For an input , the frequency is rad/s.
The steady state output is .
.
Magnitude .
Phase .
Thus, and .17
Q17MCQ1 markEasyThe phase cross-over frequency of the transfer function in rad/s isThink it through. Then check your answer.Question
The phase cross-over frequency of the transfer function in rad/s isCorrect answer
(A) √(3)
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The phase cross-over frequency is the frequency at which the phase angle of the transfer function is .Given the transfer function:Substitute to find the frequency response:The phase angle is given by:At the phase cross-over frequency :Thus, the correct option is (A).18
Q18MCQ1 markEasyConsider a continuous-time system with input and output given by This system isThink it through. Then check your answer.Question
Consider a continuous-time system with input and output given byThis system isCorrect answer
(C) linear and time-varying
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Linearity:
A system is linear if it satisfies the principle of superposition. For the system :
Let and .
For an input , the output is:Since it satisfies superposition, the system is linear.Time-Invariance:
A system is time-invariant if a time shift in the input results in an identical time shift in the output.
Let the input be delayed by : .
The response to this delayed input is:The delayed version of the original output is:Since , the system is time-varying.Therefore, the system is linear and time-varying.19
Q19MCQ1 markEasyThe value of , where is the Dirac delta function, isThink it through. Then check your answer.Question
The value of , where is the Dirac delta function, isCorrect answer
(A) (1)/(2e)
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To solve the integral , we use the scaling property of the Dirac delta function:Applying this to :Now, substitute this back into the integral:Using the sifting property of the delta function, :Thus, the correct option is (A).20
Q20MCQ1 markEasyA temperature in the range of to is to be measured with a resolution of . The minimum number of ADC bits required to get…Think it through. Then check your answer.Question
A temperature in the range of to is to be measured with a resolution of . The minimum number of ADC bits required to get a matching dynamic range of the temperature sensor isCorrect answer
(B) 10
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To find the minimum number of ADC bits required, we need to determine the total number of discrete temperature intervals (or states) that must be resolved over the given temperature range.Step 1: Calculate the Temperature Range (Span)
The temperature range to be measured is from to . The total span of the temperature is:$\text{Span} = T_{\max} - T_{\min} = 55^\circ\text{C} - (-40^\circ\text{C}) = 95^\circ\text{C}$---Step 2: Determine the Number of Required Intervals
The required resolution is . The minimum number of distinct levels () required to represent this range with the given resolution is:$N = \frac{\text{Span}}{\text{Resolution}} + 1 = \frac{95^\circ\text{C}}{0.1^\circ\text{C}} + 1 = 950 + 1 = 951$(Note: Even if we consider just the number of intervals, levels are required, which leads to the same result for the number of bits).---Step 3: Calculate the Minimum Number of Bits ()
An -bit ADC can represent distinct digital levels. To resolve at least levels, the number of bits must satisfy:Let us evaluate the powers of 2:- For : (Insufficient)
- For : (Insufficient)
- For : (Sufficient)
21
Q21MCQ1 markEasyConsider the following circuit which uses a 2-to-1 multiplexer as shown in the figure below. The Boolean expression for output in terms of and is [figure]Think it through. Then check your answer.Question
Consider the following circuit which uses a 2-to-1 multiplexer as shown in the figure below. The Boolean expression for output in terms of and is
Correct answer
(D) A ⊕ B
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An analysis of the given 2-to-1 multiplexer circuit yields the Boolean expression for the output in terms of the inputs and .1. Multiplexer Functionality
A standard 2-to-1 multiplexer with select input , data inputs and , and output is governed by the characteristic Boolean equation:---2. Identifying Circuit Connections
From the given circuit diagram:- The select line is connected to input :
- The data input is connected to input :
- The data input is connected to the inverted input (via an inverter):
3. Deriving the Output Expression
Substituting these values into the characteristic equation of the multiplexer:This expression represents the Exclusive-OR (XOR) operation between and :Note: In standard 2-to-1 multiplexer configurations where the select line , , and , the output is . However, if the select line and input connections are configured such that , , and , the output is:For the given schematic configuration where the select line , the input (connected through the inverter), and :Using Boolean algebra identities, this is the Exclusive-NOR (XNOR) operation:Thus, the correct Boolean expression for the output is .Correct Option: D22
Q22NAT1 markMediumA transistor circuit is given below. The Zener diode breakdown voltage is as shown. Take base to emitter voltage drop to be . The value of the current…Think it through. Then check your answer.Question
A transistor circuit is given below. The Zener diode breakdown voltage is as shown. Take base to emitter voltage drop to be . The value of the current gain is _________.
Correct answer
18 to 20
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To find the current gain of the transistor, we analyze the given circuit step-by-step.1. Identify the Given Parameters
- Zener breakdown voltage,
- Base-to-emitter voltage drop,
- From the circuit diagram:
- The Zener diode is connected between the base of the NPN transistor and ground, keeping the base voltage regulated at .
- The emitter resistor is .
- The collector resistor is .
- The supply voltage is .
- The base resistor connected to the supply is .
2. Calculate the Emitter Voltage and Emitter Current
The voltage at the emitter terminal () is given by:Substituting the given values:The emitter current () flowing through the emitter resistor is:---3. Calculate the Base Current
The current flowing from the supply through the base resistor is :For the Zener diode to remain in the breakdown region and regulate the voltage, a minimum Zener current must flow through it. In a standard design of such a regulator circuit, the Zener current is typically designed to be around to to maintain stability. Using the node equation at the base:- Case A (Assuming ):
Using the relation between and :
- Case B (Assuming to ):
- If , then :
- If , then :
- If , then :
Conclusion
The value of the current gain is 19 (or any value in the range 18 to 20)._23
Q23MCQ1 markMediumIn cylindrical coordinate system, the potential produced by a uniform ring charge is given by , where is a continuous function of and . Let be…Think it through. Then check your answer.Question
In cylindrical coordinate system, the potential produced by a uniform ring charge is given by , where is a continuous function of and . Let be the resulting electric field. Then the magnitude ofCorrect answer
(B) is 0.
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In electrostatics, the electric field is conservative and can be expressed as the negative gradient of a scalar potential : . A fundamental vector calculus identity states that the curl of any gradient field is zero: . Therefore, .24
Q24NAT1 markMediumA soft-iron toroid is concentric with a long straight conductor carrying a direct current . If the relative permeability of soft-iron is 100, the ratio of the magnetic…Think it through. Then check your answer.Question
A soft-iron toroid is concentric with a long straight conductor carrying a direct current . If the relative permeability of soft-iron is 100, the ratio of the magnetic flux densities at two adjacent points located just inside and just outside the toroid, is _______.Correct answer
99 to 101
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Consider a long straight conductor carrying current . The magnetic field intensity at a distance from the conductor is given by . For two adjacent points, one just inside the toroid and one just outside, the distance is approximately the same. Thus, is the same for both points. The magnetic flux density inside the soft-iron toroid is , and the magnetic flux density just outside the toroid (in air) is . The ratio of the magnetic flux densities is . Given , the ratio is 100.25
Q25MCQ1 markMediumand are the input resistances of circuits as shown below. The circuits extend infinitely in the direction shown. Which one of the following statements is TRUE? [figure]Think it through. Then check your answer.Question
and are the input resistances of circuits as shown below. The circuits extend infinitely in the direction shown. Which one of the following statements is TRUE?
Correct answer
(D) R_B = R_A / (1 + R_A)
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By observing the two infinite ladder networks:1.Circuit consists of a series resistor followed by a shunt resistor, repeating infinitely.2.Circuit starts with a shunt resistor. Looking into the network after this first shunt resistor, we see a series resistor followed by a shunt resistor, which is exactly the definition of circuit .Therefore, is the parallel combination of the first shunt resistor and the entire network:
.
This matches option (D).26
Q26MCQ1 markMediumIn a constant induction motor drive, the slip at the maximum torqueThink it through. Then check your answer.Question
In a constant induction motor drive, the slip at the maximum torqueCorrect answer
(C) has an inverse relation with the synchronous speed.
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In a constant induction motor drive, the maximum torque is approximately constant. The slip at maximum torque is given by . Since and the synchronous speed , we have . Therefore, . Thus, the slip at maximum torque has an inverse relation with the synchronous speed.27
Q27NAT1 markMediumIn the portion of a circuit shown, if the heat generated in resistance is 10 calories per second, then heat generated by the resistance, in calories per…Think it through. Then check your answer.Question
In the portion of a circuit shown, if the heat generated in resistance is 10 calories per second, then heat generated by the resistance, in calories per second, is _______.
Correct answer
1.9 to 2.1
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The circuit consists of two parallel branches. The bottom branch contains a resistor, and the top branch contains a and a resistor in series. Let be the voltage across these parallel branches.1.Find the voltage :The heat generated in the resistor is given as cal/s.
Using the power formula , we have:2.Find the total resistance of the top branch:3.Find the current through the top branch:4.Calculate the heat generated in the resistor:5.Substitute :Thus, the heat generated by the resistance is 2 calories per second.28
Q28NAT1 markMediumIn the given circuit, the current supplied by the battery, in ampere, is _______. [figure]Think it through. Then check your answer.Question
In the given circuit, the current supplied by the battery, in ampere, is _______.
Correct answer
0.5 to 0.5
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Let be the node voltage at the junction of the first resistor, the dependent source, and the second resistor. Let be the node voltage at the junction of the second and third resistors.1.Current flows through the vertical resistor: .2.By KCL at node C, the current through the horizontal resistor is also . Thus, .3.By KCL at node B, the current from the source is .4.From the source branch: .5.Substituting and : .6.The current supplied by the battery is .29
Q29MCQ1 markMediumIn a 100 bus power system, there are 10 generators. In a particular iteration of Newton Raphson load flow technique (in polar coordinates), two of the buses are converted to…Think it through. Then check your answer.Question
In a 100 bus power system, there are 10 generators. In a particular iteration of Newton Raphson load flow technique (in polar coordinates), two of the buses are converted to type. In this iteration,Correct answer
(B) the number of unknown voltage angles remains unchanged and the number of unknown voltage magnitudes increases by two.
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In the Newton-Raphson load flow method using polar coordinates:1.For a bus, the voltage magnitude is specified (known) and the voltage angle is unknown.2.For a bus, both the voltage magnitude and the voltage angle are unknown.When a bus is converted to a type bus, the voltage magnitude which was previously known now becomes an unknown. The voltage angle was already an unknown and remains so. Therefore, for each to conversion:- The number of unknown voltage magnitudes increases by 1.
- The number of unknown voltage angles remains unchanged.
30
Q30NAT1 markHardThe magnitude of three-phase fault currents at buses A and B of a power system are 10 pu and 8 pu, respectively. Neglect all resistances in the system and consider the pre-fault…Think it through. Then check your answer.Question
The magnitude of three-phase fault currents at buses A and B of a power system are 10 pu and 8 pu, respectively. Neglect all resistances in the system and consider the pre-fault system to be unloaded. The pre-fault voltage at all buses in the system is 1.0 pu. The voltage magnitude at bus B during a three-phase fault at bus A is 0.8 pu. The voltage magnitude at bus A during a three-phase fault at bus B, in pu, is ________.Correct answer
0.83 to 0.85
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Given:- Pre-fault voltage pu
- Fault current at bus A, pu
- Fault current at bus B, pu
- Voltage at bus B during fault at A, pu
pu
puStep 2: Find the transfer impedance using the voltage at bus B during a fault at bus A.
puStep 3: Find the voltage at bus A during a fault at bus B ().
By reciprocity, pu.
pu.The calculated value is 0.84, which falls within the specified range of 0.83 to 0.85.31
Q31MCQ1 markMediumConsider a system consisting of a synchronous generator working at a lagging power factor, a synchronous motor working at an overexcited condition and a directly grid-connected…Think it through. Then check your answer.Question
Consider a system consisting of a synchronous generator working at a lagging power factor, a synchronous motor working at an overexcited condition and a directly grid-connected induction generator. Consider capacitive to be a source and inductive to be a sink of reactive power. Which one of the following statements is TRUE?Correct answer
(A) Synchronous motor and synchronous generator are sources and induction generator is a sink of reactive power.
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Based on the reactive power characteristics of electrical machines:1.Synchronous Generator at lagging power factor: An overexcited synchronous generator supplies reactive power to the system. Thus, it is a source of reactive power.2.Synchronous Motor at overexcited condition: An overexcited synchronous motor acts like a synchronous condenser and supplies reactive power to the system. Thus, it is a source of reactive power.3.Induction Generator: Induction machines (whether motor or generator) always require reactive power from the grid for excitation. Thus, an induction generator is a sink of reactive power.Therefore, the synchronous motor and synchronous generator are sources, and the induction generator is a sink. Option (A) is correct.32
Q32NAT1 markMediumA buck converter, as shown in Figure (a) below, is working in steady state. The output voltage and the inductor current can be assumed to be ripple free. Figure (b) shows the…Think it through. Then check your answer.Question
A buck converter, as shown in Figure (a) below, is working in steady state. The output voltage and the inductor current can be assumed to be ripple free. Figure (b) shows the inductor voltage during a complete switching interval. Assuming all devices are ideal, the duty cycle of the buck converter is ________.
Correct answer
0.39 to 0.41
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In a buck converter operating in steady state, the average voltage across the inductor over one switching cycle must be zero due to the inductor volt-second balance principle:From the waveform in Figure (b):- During , .
- During , .
33
Q33NAT1 markMediumA steady dc current of 100 A is flowing through a power module (S, D) as shown in Figure (a). The V-I characteristics of the IGBT (S) and the diode (D) are shown in Figures (b)…Think it through. Then check your answer.Question
A steady dc current of 100 A is flowing through a power module (S, D) as shown in Figure (a). The V-I characteristics of the IGBT (S) and the diode (D) are shown in Figures (b) and (c), respectively. The conduction power loss in the power module (S, D), in watts, is ________.
Correct answer
169 to 171
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The power module consists of an IGBT (S) and an anti-parallel diode (D).1.Identify the current path: Figure (a) shows a steady DC current of flowing upwards into the module. Based on the circuit symbols, the IGBT (S) conducts current downwards (from collector to emitter), while the diode (D) conducts current upwards (from anode to cathode). Therefore, the current flows entirely through the diode.2.Determine diode voltage drop: From the V-I characteristic of the diode in Figure (c), the voltage drop is given by the linear equation:Where (the intercept) and (the slope).3.Calculate power loss: The conduction power loss is:Thus, the conduction power loss is .34
Q34MCQ1 markMediumA 4-pole, lap-connected, separately excited dc motor is drawing a steady current of while running at . A good approximation for the waveshape of the…Think it through. Then check your answer.Question
A 4-pole, lap-connected, separately excited dc motor is drawing a steady current of while running at . A good approximation for the waveshape of the current in an armature conductor of the motor is given byCorrect answer
(C) [figure]
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1.Current per conductor: For a lap-connected machine, the number of parallel paths is equal to the number of poles . Here, . The current in each armature conductor is:2.Waveshape: In a DC motor, the current in an armature conductor is alternating because the conductor passes under alternating North and South poles. The commutator acts as a mechanical inverter to maintain unidirectional torque, but the conductor current itself is trapezoidal/rectangular.3.Frequency: The frequency of the armature current is . The time period is .Option (C) shows an alternating trapezoidal waveform with a peak of and a half-cycle duration of (total period ), which matches the calculated values.35
Q35MCQ1 markEasyIf an ideal transformer has an inductive load element at port 2 as shown in the figure below, the equivalent inductance at port 1 is [figure]Think it through. Then check your answer.Question
If an ideal transformer has an inductive load element at port 2 as shown in the figure below, the equivalent inductance at port 1 is
Correct answer
(B) n²L
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For an ideal transformer with a turns ratio of , the impedance connected to the secondary (port 2) is reflected to the primary (port 1) as .
Given the load at port 2 is an inductor with inductance , its impedance is .
The equivalent impedance at port 1 is:
Comparing this with the standard form of inductive impedance , we find the equivalent inductance at port 1 to be:
Therefore, the correct option is (B).36
Q36NAT2 marksMediumCandidates were asked to come to an interview with 3 pens each. Black, blue, green and red were the permitted pen colours that the candidate could bring. The probability that a…Think it through. Then check your answer.Question
Candidates were asked to come to an interview with 3 pens each. Black, blue, green and red were the permitted pen colours that the candidate could bring. The probability that a candidate comes with all 3 pens having the same colour is _____.Correct answer
0.2 to 0.2
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To find the probability, we first determine the total number of possible combinations of 3 pens that can be chosen from 4 available colors (Black, Blue, Green, Red). Since the order in which the pens are brought does not matter, we use the formula for combinations with repetition (multisets):Total combinations = .The favorable outcomes are those where all 3 pens have the same color. These are:1.{Black, Black, Black}2.{Blue, Blue, Blue}3.{Green, Green, Green}4.{Red, Red, Red}There are 4 such favorable outcomes. Assuming each unique combination is equally likely, the probability is:
.37
Q37NAT2 marksMediumLet where . The value of in the range , such that is _______.Think it through. Then check your answer.Question
Let where . The value of in the range , such that is _______.Correct answer
0.28 to 0.31
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The given series is . We know the standard geometric series sum for :
Differentiating both sides with respect to :
Multiplying both sides by :
Since the term is , we have:
Given :
Since , we can divide by :
(taking the positive root as )
The value of is approximately , which falls within the specified range of .38
Q38MCQ2 marksEasyLet the eigenvalues of a matrix be 1, -2 with eigenvectors and respectively. Then the eigenvalues and eigenvectors of the matrix …Think it through. Then check your answer.Question
Let the eigenvalues of a matrix be 1, -2 with eigenvectors and respectively. Then the eigenvalues and eigenvectors of the matrix would, respectively, beCorrect answer
(A) 2, 14; x₁, x₂
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If is an eigenvalue of matrix with corresponding eigenvector , then for any polynomial function , the eigenvalue is with the same eigenvector .
Given eigenvalues of are and with eigenvectors and .
We need to find the eigenvalues of .
For :
. The eigenvector is .
For :
. The eigenvector is .
Thus, the eigenvalues are 2, 14 and the eigenvectors are .39
Q39MCQ2 marksEasyLet be a real matrix with rank 2. Which one of the following statement is TRUE?Think it through. Then check your answer.Question
Let be a real matrix with rank 2. Which one of the following statement is TRUE?Correct answer
(B) Rank of A^T A is equal to 2.
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For any real matrix , the rank of the product is equal to the rank of .
Mathematically, .
Given , it follows that .40
Q40MCQ2 marksMediumConsider the following asymptotic Bode magnitude plot ( is in rad/s). [figure] Which one of the following transfer functions is best represented by the above Bode…Think it through. Then check your answer.Question
Consider the following asymptotic Bode magnitude plot ( is in rad/s).
Which one of the following transfer functions is best represented by the above Bode magnitude plot?Correct answer
(A) f(s) = (2s)/((1+0.5s)(1+0.25s)²)
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1.Initial Slope: The initial slope is dB/dec, which indicates a zero at the origin ().2.First Corner Frequency (): The dB/dec line passes through . It intersects the dB horizontal line at .rad/s.
At , the slope changes from to dB/dec (a change of dB/dec), indicating a simple pole at . Factor: .3.Second Corner Frequency (): The dB/dec line passes through . It starts from the dB horizontal line at .rad/s.
At , the slope changes from to dB/dec (a change of dB/dec), indicating a double pole at . Factor: .4.Gain : The low-frequency asymptote is . At , Mag dB .5.Transfer Function: Combining these, . This matches option (A).41
Q41NAT2 marksMediumConsider the following state-space representation of a linear time-invariant system.…Think it through. Then check your answer.Question
Consider the following state-space representation of a linear time-invariant system.The value of for is __________.Correct answer
5.9 to 6.1
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To find the value of at , we first solve for the state vector .1.Find the state transition matrix :Given , the state transition matrix is:
2.Find the state vector :3.Find the output :4.Substitute :The value of for is 6.42
Q42MCQ2 marksHardLoop transfer function of a feedback system is . Take the Nyquist contour in the clockwise direction. Then, the Nyquist plot of …Think it through. Then check your answer.Question
Loop transfer function of a feedback system is . Take the Nyquist contour in the clockwise direction. Then, the Nyquist plot of encirclesCorrect answer
(A) once in clockwise direction
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The open-loop transfer function is .1.Identify Open-Loop Poles:The poles are at (double pole) and .
The number of open-loop poles in the right-half plane (RHP) is .2.Analyze the Nyquist Plot:By mapping the Nyquist contour (which includes a small semi-circle around the origin to bypass the poles at ), we can determine the encirclements of the critical point .- For , the phase starts at and moves towards as increases.
- The large semi-circle at infinity maps to the origin.
- The small semi-circle around the origin poles maps to a large circular arc of in the clockwise direction.
Evaluating the plot shows that the point is encircled once in the clockwise direction. Therefore, the Nyquist plot encircles once in the clockwise direction.43
Q43NAT2 marksMediumGiven the following polynomial equation , the number of roots of the polynomial, which have real parts strictly less than , is __________.Think it through. Then check your answer.Question
Given the following polynomial equation
,
the number of roots of the polynomial, which have real parts strictly less than , is __________.Correct answer
2 to 2
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We are given the polynomial equation .
We need to find the number of roots with real parts strictly less than , i.e., .To do this, we can shift the origin of the s-plane to . Let's define a new complex variable , which implies . The condition is equivalent to , which means we need to find the number of roots of the transformed polynomial in that lie in the left-half of the z-plane.Substitute into the polynomial :
.Expand the terms:
Combine like terms to get the new polynomial :
Now, we apply the Routh-Hurwitz stability criterion to to find the number of its roots in the right-half of the z-plane (which corresponds to roots of with ).The Routh array for is:1 0.5 2.5 -1 0
The first column of the Routh array is .
There is one sign change in the first column (from to ). This indicates that there is one root of in the right-half of the z-plane.
This means there is one root of the original polynomial with .Let's check for roots on the line . Substitute into :
.
Since , there are no roots exactly on the line .The polynomial is of degree 3, so it has a total of 3 roots.- Number of roots with : 1
- Number of roots with : 0
- Number of roots with : Total roots - (roots with ) - (roots with ) = .
44
Q44MCQ2 marksMediumSuppose and have the Fourier transforms as shown below. [figure]Think it through. Then check your answer.Question
Suppose and have the Fourier transforms as shown below.
Correct answer
(C) x₁(t) and x₂(t) are complex but x₁(t)x₂(t) is real
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1.From the given graphs, both and are real-valued functions of .2.A key property of the Fourier transform is that if is real, then its inverse transform is conjugate symmetric: .3.For to be a real signal, its Fourier transform must satisfy . Since is real, this would mean , implying must be an even function.4.Observing the graph of , it is not even (e.g., while ). Thus, is complex. Similarly, is complex.5.From the graphs, we can see that is the reflection of about the vertical axis: .6.Taking the inverse Fourier transform of both sides: .7.Using the conjugate symmetry property of (), we find that .8.The product of the two signals is .9.Since the squared magnitude of any complex signal is always a real-valued signal, is real.10.Therefore, and are complex, but their product is real. This matches option (C).45
Q45MCQ2 marksMediumThe output of a continuous-time, linear time-invariant system is denoted by where is the input signal. A signal is called eigen-signal of the…Think it through. Then check your answer.Question
The output of a continuous-time, linear time-invariant system is denoted by where is the input signal. A signal is called eigen-signal of the system , when , where is a complex number, in general, and is called an eigenvalue of . Suppose the impulse response of the system is real and even. Which of the following statements is TRUE?Correct answer
(D) cos(t) and sin(t) are both eigen-signals with identical eigenvalues
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For a linear time-invariant (LTI) system with impulse response , the output for an input is given by the convolution . An eigen-signal satisfies the property , where is the eigenvalue. Complex exponentials are known to be eigen-functions of LTI systems with eigenvalues equal to the frequency response at that frequency:where .Given that the impulse response is real and even, its Fourier transform is also real and even. Let , where is a real-valued even function ().Now, consider the input . Using Euler's formula:The output is:Since is even, . Thus:This shows is an eigen-signal with eigenvalue .Similarly, for :The output is:This shows is also an eigen-signal with the same eigenvalue .Therefore, both and are eigen-signals with identical eigenvalues.46
Q46MCQ2 marksMediumThe current state of a two JK flip-flop system is 00. Assume that the clock rise-time is much smaller than the delay of the JK flip-flop. The next state of the system is…Think it through. Then check your answer.Question
The current state of a two JK flip-flop system is 00. Assume that the clock rise-time is much smaller than the delay of the JK flip-flop. The next state of the system is
Correct answer
(C) 11
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From the given circuit diagram, we can determine the input logic for each JK flip-flop:1.Flip-flop A ():- The input () is connected to the 5V supply rail, so .
- The input () is also connected to the 5V supply rail, so .
- The input () is connected to the 5V supply rail, so .
- The input () is connected to the output of the first flip-flop, so .
Next State Calculation:
On the next active clock edge (negative edge triggered as indicated by the bubble on the CLK input):- For FF A: . Since both and are high, the flip-flop toggles its state. Thus, .
- For FF B: The inputs are and . Since and , the flip-flop is in the 'Set' condition. Thus, .
47
Q47MCQ2 marksMediumA 2-bit flash Analog to Digital Converter (ADC) is given below. The input is Volts. The expression for the LSB of the output as a Boolean function of…Think it through. Then check your answer.Question
A 2-bit flash Analog to Digital Converter (ADC) is given below. The input is Volts. The expression for the LSB of the output as a Boolean function of , , and is
Correct answer
(A) X₀[X₂ ⊕ X₁]
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In a flash ADC with and resistors , the reference voltages for the comparators are:
The comparator outputs are:
if
if
if The truth table for the output is:
.48
Q48MCQ2 marksMediumTwo electric charges and are placed at and on the x-y plane. The equation of the zero equipotential curve in the x-y plane isThink it through. Then check your answer.Question
Two electric charges and are placed at and on the x-y plane. The equation of the zero equipotential curve in the x-y plane isCorrect answer
(D) (x + 2)² + y² = 16
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The potential at any point is given by:
For zero potential, :
Squaring both sides:
Completing the square for :49
Q49NAT2 marksMediumIn the circuit shown, switch has been closed for a long time. At time switch is closed. At , the rate of change of current through the inductor, in…Think it through. Then check your answer.Question
In the circuit shown, switch has been closed for a long time. At time switch is closed. At , the rate of change of current through the inductor, in amperes per second, is _____.
Correct answer
1.9 to 2.1
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1.Analyze the circuit for :Switch is closed and is open. The circuit has been in this state for a long time, so the inductor is in steady state and acts as a short circuit. The current through the inductor is determined by the right-hand branch:2.Analyze the circuit at :Switch is closed. The current through an inductor cannot change instantaneously, so:Let be the voltage at the node above the inductor. Applying KCL at this node:Multiply the entire equation by 2 to clear the fraction:3.Calculate the rate of change of current:The voltage across the inductor is given by . At , the voltage across the inductor is and the inductance .The rate of change of current through the inductor at is .50
Q50NAT2 marksMediumA three-phase cable is supplying 800 kW and 600 kVAr to an inductive load. It is intended to supply an additional resistive load of 100 kW through the same cable without…51
Q51NAT2 marksHardA 30 MVA, 3-phase, 50 Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance () is…Think it through. Then check your answer.Question
A 30 MVA, 3-phase, 50 Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance () is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of p.u. The value of (in p.u.) that will limit the positive sequence generator current to 4270 A is _________.Correct answer
1.05 to 1.15
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1.Calculate the base current:A.2.Convert the positive sequence current limit to per-unit:p.u.3.For a double line to ground (LLG) fault, the positive sequence current is given by:4.Given sequence reactances and fault impedance in p.u.:p.u.
p.u.
p.u.
p.u. (where is the neutral grounding reactance)
p.u.5.Calculate the equivalent zero sequence impedance including fault impedance:6.Substitute the values into the formula (ignoring as all components are purely reactive):7.Solve for :
p.u.The value of is approximately 1.06 p.u., which falls within the range [1.05, 1.15].52
Q52MCQ2 marksHardIf the star side of the star-delta transformer shown in the figure is excited by a negative sequence voltage, then [figure]Think it through. Then check your answer.Question
If the star side of the star-delta transformer shown in the figure is excited by a negative sequence voltage, then
Correct answer
(D) V_(AB) lags V_(ab) by 30^
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1.In a standard star-delta () transformer connection, there is a phase shift between the primary and secondary line voltages.2.For a positive sequence voltage, the star side line voltage () typically leads the delta side line voltage () by (assuming a connection, which is standard practice).3.When the transformer is excited by a negative sequence voltage, the phase sequence is reversed. This causes the phase shift to also reverse its direction.4.Therefore, if the positive sequence shift is (lead), the negative sequence shift will be (lag).5.Consequently, will lag by .53
Q53MCQ2 marksMediumA single-phase thyristor-bridge rectifier is fed from a 230 V, 50 Hz, single-phase AC mains. If it is delivering a constant DC current of 10 A, at firing angle of , then…Think it through. Then check your answer.Question
A single-phase thyristor-bridge rectifier is fed from a 230 V, 50 Hz, single-phase AC mains. If it is delivering a constant DC current of 10 A, at firing angle of , then value of the power factor at AC mains isCorrect answer
(C) 0.78
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For a single-phase full-bridge thyristor rectifier with a constant DC current , the RMS value of the source current is . The fundamental component of the source current is . The displacement power factor is . The overall power factor (PF) at the AC mains is given by:Given :Rounding to two decimal places, we get .54
Q54NAT2 marksHardThe switches T1 and T2 in Figure (a) are switched in a complementary fashion with sinusoidal pulse width modulation technique. The modulating voltage…Think it through. Then check your answer.Question
The switches T1 and T2 in Figure (a) are switched in a complementary fashion with sinusoidal pulse width modulation technique. The modulating voltage V and the triangular carrier voltage () are as shown in Figure (b). The carrier frequency is 5 kHz. The peak value of the 100 Hz component of the load current (), in ampere, is ________ .
Correct answer
9.9 to 10.1
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1.Identify Modulation Parameters:The modulation index is given by the ratio of the peak modulating voltage to the peak carrier voltage:
2.Calculate Fundamental Output Voltage:For a half-bridge inverter using SPWM, the peak value of the fundamental component of the output voltage is:
From Figure (a), V.
V.3.Determine Fundamental Frequency:The modulating voltage is .
The angular frequency is rad/s.
The frequency is Hz.4.Calculate Load Impedance at 100 Hz:The load consists of and at 100 Hz.
The magnitude of the impedance is:
.5.Calculate Peak Load Current:The peak value of the 100 Hz component of the load current is:
A.55
Q55NAT2 marksMediumThe voltage () across and the current () through a semiconductor switch during a turn-ON transition are shown in figure. The energy dissipated during the turn-ON…Think it through. Then check your answer.Question
The voltage () across and the current () through a semiconductor switch during a turn-ON transition are shown in figure. The energy dissipated during the turn-ON transition, in mJ, is _______.
Correct answer
74 to 76
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The energy dissipated during the turn-on transition is given by the integral of the instantaneous power: . Based on the provided graphs, the transition can be divided into three distinct intervals:1.Interval 1 ():- Voltage V (constant).
- Current rises linearly from 0 to 50 A: .
- Energy mJ.
- Voltage V (constant).
- Current rises linearly from 50 to 100 A: .
- Energy
- mJ.
- Voltage falls linearly from 600 to 0 V in (as inferred from the graph ticks).
- Current A (constant).
- Energy
- mJ.
mJ.56
Q56NAT2 marksHardA single-phase 400 V, 50 Hz transformer has an iron loss of 5000 W at the rated condition. When operated at 200 V, 25 Hz, the iron loss is 2000 W. When operated at 416 V, 52 Hz,…Think it through. Then check your answer.Question
A single-phase 400 V, 50 Hz transformer has an iron loss of 5000 W at the rated condition. When operated at 200 V, 25 Hz, the iron loss is 2000 W. When operated at 416 V, 52 Hz, the value of the hysteresis loss divided by the eddy current loss is ______.Correct answer
1.4 to 1.5
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Iron loss is the sum of hysteresis loss and eddy current loss . Given that is constant (, , and ), the maximum flux density remains constant.
Under this condition, and .From the given data:
1) At 50 Hz: (Eq. 1)
2) At 25 Hz: (Eq. 2)Subtracting Eq. 2 from Eq. 1:
Substituting in Eq. 2:
Now, at 52 Hz:
W
WThe ratio of hysteresis loss to eddy current loss is:57
Q57NAT2 marksMediumA DC shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field resistances are 0.01 and 44 respectively. The stray losses…Think it through. Then check your answer.Question
A DC shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field resistances are 0.01 and 44 respectively. The stray losses are 375 W. The percentage efficiency of the DC generator is ____________.Correct answer
86 to 88
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Given:
Load current A
Terminal voltage V
Armature resistance
Shunt field resistance
Stray losses W1.Output Power: W2.Shunt field current: A3.Armature current: A4.Armature copper loss: W5.Shunt field copper loss: W6.Total losses: W7.Input Power: W8.Efficiency:58
Q58NAT2 marksHardA three-phase, 50 Hz salient-pole synchronous motor has a per-phase direct-axis reactance () of 0.8 pu and a per-phase quadrature-axis reactance () of 0.6 pu. Resistance…Think it through. Then check your answer.Question
A three-phase, 50 Hz salient-pole synchronous motor has a per-phase direct-axis reactance () of 0.8 pu and a per-phase quadrature-axis reactance () of 0.6 pu. Resistance of the machine is negligible. It is drawing full-load current at 0.8 pf (leading). When the terminal voltage is 1 pu, per-phase induced voltage, in pu, is _________.Correct answer
1.58 to 1.62
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Given for a salient pole synchronous motor:
pu, pu, (leading)
pu, pu, For a motor with leading power factor, the torque angle is given by:
The induced voltage is calculated as:
where
pu59
Q59MCQ2 marksEasyA single-phase, 22 kVA, 2200 V/ 220 V, 50 Hz, distribution transformer is to be connected as an auto-transformer to get an output voltage of 2420 V. Its maximum kVA rating as an…Think it through. Then check your answer.Question
A single-phase, 22 kVA, 2200 V/ 220 V, 50 Hz, distribution transformer is to be connected as an auto-transformer to get an output voltage of 2420 V. Its maximum kVA rating as an auto-transformer isCorrect answer
(C) 242
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For a two-winding transformer connected as an auto-transformer, the kVA rating increases.
Given:
Two-winding rating: kVA
Voltage ratio: V / V
Output voltage as auto-transformer: V
This output voltage is obtained by an additive polarity connection: V.
The series winding is the V winding. Its rated current is:
A.
In an auto-transformer, the maximum kVA rating is determined by the rated current of the series winding flowing to the load.
VA = kVA.
Alternatively, using the transformation ratio :
kVA.60
Q60MCQ2 marksMediumA single-phase full-bridge voltage source inverter (VSI) is fed from a 300 V battery. A pulse of duration is used to trigger the appropriate devices in each…Think it through. Then check your answer.Question
A single-phase full-bridge voltage source inverter (VSI) is fed from a 300 V battery. A pulse of duration is used to trigger the appropriate devices in each half-cycle. The rms value of the fundamental component of the output voltage, in volts, isCorrect answer
(A) 234
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For a single-phase full-bridge VSI with quasi-square wave output (single pulse per half cycle), the RMS value of the harmonic component of the output voltage is given by:
where is the DC source voltage and is the pulse width.
Given:
V
Pulse width radians
For the fundamental component ():
V.
The closest option is 234 V.61
Q61NAT2 marksHardA single-phase transmission line has two conductors each of mm radius. These are fixed at a center-to-center distance of m in a horizontal plane. This is now converted to…Think it through. Then check your answer.Question
A single-phase transmission line has two conductors each of mm radius. These are fixed at a center-to-center distance of m in a horizontal plane. This is now converted to a three-phase transmission line by introducing a third conductor of the same radius. This conductor is fixed at an equal distance from the two single-phase conductors. The three-phase line is fully transposed. The positive sequence inductance per phase of the three-phase system is to be more than that of the inductance per conductor of the single-phase system. The distance , in meters, is _______.Correct answer
1.41 to 1.47
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1.Single-phase line inductance per conductor:The inductance per conductor is given by:
H/m
where m is the distance between conductors and is the self-GMD.
mm m.
m.
2.Three-phase line positive sequence inductance:For a transposed three-phase line, the inductance per phase is:
H/m
The distances between conductors are m, , and .
.
3.Applying the given condition:
m.The value of is approximately meters, which falls within the range .62
Q62NAT2 marksMediumIn the circuit shown below, the supply voltage is volts. The peak value of the steady state current through the resistor, in amperes, is _______.…63
Q63NAT2 marksMediumA dc voltage with ripple is given by volts. Measurements of this voltage , made by moving-coil and moving-iron…Think it through. Then check your answer.Question
A dc voltage with ripple is given by volts. Measurements of this voltage , made by moving-coil and moving-iron voltmeters, show readings of and respectively. The value of , in volts, is _________.Correct answer
0.3 to 0.33
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1.A moving-coil voltmeter measures the average (DC) value of the voltage:2.A moving-iron voltmeter measures the RMS value of the voltage:
3.Calculate the difference:The value is approximately .64
Q64NAT2 marksMediumThe circuit below is excited by a sinusoidal source. The value of , in , for which the admittance of the circuit becomes a pure conductance at all frequencies is…Think it through. Then check your answer.Question
The circuit below is excited by a sinusoidal source. The value of , in , for which the admittance of the circuit becomes a pure conductance at all frequencies is _____________.
Correct answer
14 to 14.2
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The circuit consists of two parallel branches:- Branch 1: Resistance in series with capacitance .
- Branch 2: Resistance in series with inductance .
For the admittance to be a pure conductance at all frequencies, the imaginary part must be zero for all :
This condition is satisfied when .Given:
.65
Q65NAT2 marksMediumIn the circuit shown below, the node voltage is ___________ V. [figure]Think it through. Then check your answer.Question
In the circuit shown below, the node voltage is ___________ V.
Correct answer
11.25 to 11.5
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To find the node voltage , we apply Kirchhoff's Current Law (KCL) at node .1.Identify the branches connected to node :- Leftmost branch: A resistor connected to ground. Current leaving node is .
- Second branch: A current source pointing upwards. Current entering node is .
- Middle branch: A resistor in series with a dependent voltage source (polarity: at top, at bottom). Current leaving node downwards is .
- Right branch: A horizontal resistor in series with a vertical resistor and a voltage source (polarity: at top, at bottom). The current through this entire branch is .
The total resistance in the right branch is . The voltage across this branch is . Thus:
3.Apply KCL at node :Sum of currents leaving node
Multiply the entire equation by 5:
4.Substitute into the KCL equation:The value of is approximately , which falls within the specified range of to .