Question text and figures as in the official paper, with the answer from the official key. Worked solutions for every question are in your report after you take the paper as a 3-hour test.
In this sentence, the word ‘lemons’ is the ________.
(A)
object
(B)
subject
(C)
predicate
(D)
verb
Answer (official key): A
Worked solution: in your report after you take this paper.
Q2 · General Aptitude · MCQ · 1 mark
The figure below is supposed to show three non-overlapping shapes – one oval and two triangles. Which one of the following figures P, Q, R, or S fits the missing portion indicated by ‘?’ and completes the oval and the two triangles?
(A)
P
(B)
Q
(C)
R
(D)
S
Answer (official key): A
Worked solution: in your report after you take this paper.
Q3 · General Aptitude · MCQ · 1 mark
At how many points will the curves y=x2 and y=−x2−2x−1 intersect in the real (x,y) plane?
(A)
0
(B)
1
(C)
2
(D)
3
Answer (official key): A
Worked solution: in your report after you take this paper.
Q4 · General Aptitude · MCQ · 1 mark
‘If Anish had scored hundred runs in today’s match, he would have been made the captain of his team. He would have then become the youngest captain in his team’s history. Unfortunately, he got out without scoring any runs. Hence, there won’t be any change in the captaincy for now.’
Based on the paragraph above, which one of the following statements is true?
(A)
Anish made hundred runs but was denied captaincy.
(B)
Anish was the captain of his team before the game today.
(C)
The current captain is older than Anish.
(D)
Anish is the youngest player in his team.
Answer (official key): C
Worked solution: in your report after you take this paper.
Q5 · General Aptitude · MCQ · 1 mark
Which one of the following figures P, Q, R, or S, correctly shows the 45° clockwise-rotated version of figure (I)?
(A)
P
(B)
Q
(C)
R
(D)
S
Answer (official key): B
Worked solution: in your report after you take this paper.
Q6 · General Aptitude · MCQ · 2 marks
Match the words in Column I with their synonyms in Column II.
Column I
Column II
(i) Lonely
(p) Verbatim
(ii) Literal
(q) Solitary
(iii) Lousy
(r) Deadly
(iv) Lethal
(s) Terrible
(A)
(i)-(q); (ii)-(p); (iii)-(s); (iv)-(r)
(B)
(i)-(q); (ii)-(s); (iii)-(r); (iv)-(p)
(C)
(i)-(s); (ii)-(p); (iii)-(q); (iv)-(r)
(D)
(i)-(r); (ii)-(s); (iii)-(p); (iv)-(q)
Answer (official key): A
Worked solution: in your report after you take this paper.
Q7 · General Aptitude · MCQ · 2 marks
In the given figure, PQ is the diameter of a circle with center O. Two points R and S are chosen on the circle such that ∠ROS=80∘. When PR and QS are extended, they meet at T. The value of ∠RTS is _________________
(A)
40°
(B)
50°
(C)
60°
(D)
80°
Answer (official key): B
Worked solution: in your report after you take this paper.
Q8 · General Aptitude · MCQ · 2 marks
Based on the relationship between each polygon and the number inside it, the value of ‘X’ is ______
(A)
720
(B)
596
(C)
24
(D)
240
Answer (official key): A
Worked solution: in your report after you take this paper.
Q9 · General Aptitude · MCQ · 2 marks
Consider a linear arrangement of seven bulbs, each of which can be in the ON or OFF states. The initial configuration of the bulbs is shown in the figure. In every Step, the states of the bulbs are changed based on the following rules:
Any OFF bulb with exactly one ON neighbor at the end of the previous Step is turned ON.
Any ON bulb with both neighbors ON at the end of the previous Step is turned OFF.
The state of any bulb not meeting the conditions above is left unchanged.
The state of bulbs at the end of Step 1 and Step 2 are also shown in the figure.
The number of bulbs which are ON at the end of Step 8 is ______
(A)
5
(B)
4
(C)
3
(D)
0
Answer (official key): B
Worked solution: in your report after you take this paper.
Q10 · General Aptitude · MCQ · 2 marks
P and Q are two positive integers such that P2=Q2+13.
The product of the numbers P and Q is _________
(A)
13
(B)
26
(C)
39
(D)
42
Answer (official key): D
Worked solution: in your report after you take this paper.
Q11 · Signals and Systems · MCQ · 1 mark
Consider the infinite-length, discrete-time sequence x[n]=0.9∣n∣, where n is an integer. The region of convergence of its Z-transform X(z) is given by:
(Note: z is a complex variable)
(A)
∣z∣>0.9
(B)
∣z∣<0.9
(C)
0.9<∣z∣<1/0.9
(D)
{z such that ∣z∣<0.9}∪{z such that ∣z∣>1/0.9}
Answer (official key): C
Worked solution: in your report after you take this paper.
Q12 · Signals and Systems · MCQ · 1 mark
Let xc(t) be any continuous-time periodic signal with period T. It is sampled uniformly with a sampling period Ts where Ts=T, resulting in the discrete sequence
x[n]=xc(nTs),
where n is an integer.
Which one of the following statements is correct about x[n]?
(A)
x[n] will always be periodic with period T/Ts for all values of T/Ts
(B)
x[n] will always be periodic with period 1 for all values of T/Ts
(C)
x[n] will never be periodic
(D)
x[n] will be periodic if and only if T/Ts is a rational number
Answer (official key): D
Worked solution: in your report after you take this paper.
Q13 · Control Systems · MCQ · 1 mark
The Laplace transform of the step response of a system is given by
Y(s)=s(s+100)100
The rise time is defined as the time taken for the response to go from 0.1 to 0.9 of its final value. The settling time is defined as the time taken for the response to reach 0.98 of its final value.
For this system, the rise time (Tr), settling time (Ts), and time constant (Tc), all expressed in seconds, are
(A)
Tr=0.022, Ts=0.04, Tc=0.01
(B)
Tr=0.22, Ts=0.404, Tc=0.01
(C)
Tr=2.2, Ts=4.04, Tc=1.01
(D)
Tr=22, Ts=40.4, Tc=10.1
Answer (official key): A
Worked solution: in your report after you take this paper.
Q14 · Differential Equations · MCQ · 1 mark
Consider the following differential equation:
t2dt2d2y+7tdtdy+8ty=10sin(t)
Which one of the following options is correct?
(A)
It is a linear differential equation
(B)
It is a nonlinear differential equation
(C)
It is a time-invariant differential equation
(D)
It is a second-order partial differential equation
Answer (official key): A
Worked solution: in your report after you take this paper.
Q15 · Electromagnetic Fields · MCQ · 1 mark
A uniform ring charge of radius R carries a total charge Q. Which one of the following options correctly quantifies the magnitude of the force on a point charge of strength q kept at the center of the ring?
(ϵ is the permittivity of the medium)
(A)
4πϵRQq
(B)
4πϵR2Qq
(C)
0
(D)
4πϵRq×2πRQ
Answer (official key): C
Worked solution: in your report after you take this paper.
Q16 · Electromagnetic Fields · MCQ · 1 mark
A positive point charge with velocity v=5x^ enters a region having electric field E=4y^ and magnetic field B=−6z^. Which one of the following statements is correct for the force on the charge as it enters the region?
(A)
The force will be along the magnetic field but perpendicular to the electric field
(B)
The force will be along the electric field but perpendicular to the magnetic field
(C)
The force will be perpendicular to both electric and magnetic field
(D)
The magnetic field does not exert any force on the charge
Answer (official key): B
Worked solution: in your report after you take this paper.
Q17 · Electrical Machines · MCQ · 1 mark
A 15 kVA, 1100 V/220 V, single-phase two-winding transformer is configured as a 1.32 kV/1.1 kV autotransformer.
What will be the rating of the autotransformer?
(A)
60 kVA
(B)
75 kVA
(C)
90 kVA
(D)
100 kVA
Answer (official key): C
Worked solution: in your report after you take this paper.
Q18 · Power Systems · MCQ · 1 mark
Consider a power system with N buses, of which P are generator buses and the remaining Q are load buses (where there is no generation).
Assume that there are no reactive power-limit violations at the generator buses. What is the size of the Jacobian matrix in the Newton-Raphson load flow method?
(A)
2N×2N
(B)
(2N−1−P)×(2N−1−P)
(C)
(2N−Q)×(2N−Q)
(D)
(P+Q)×(P+Q)
Answer (official key): B
Worked solution: in your report after you take this paper.
Q19 · Power Systems · MCQ · 1 mark
The initial three-phase voltage phasors (VˉA, VˉB, and VˉC) at a bus of a power network are as shown in Case-1. Due to a disturbance, the bus voltage phasors changed in phase by a small angle Δθ, and the magnitudes remained the same as depicted in Case-2.
Which one of the following statements is correct about the zero sequence components?
(A)
The zero sequence components in Case-1 and Case-2 have the same phase angle and magnitude
(B)
The magnitude of the zero sequence component in Case-1 is greater than that in Case-2
(C)
The magnitude of the zero sequence component in Case-2 is greater than that in Case-1
(D)
The zero sequence components in Case-1 and Case-2 have the same magnitude but different phase angles
Answer (official key): D
Worked solution: in your report after you take this paper.
Q20 · Electrical Machines · MCQ · 1 mark
A certain application requires power at a frequency of 16.67 Hz, while the available grid frequency is 50 Hz. A 3-phase synchronous motor connected to the 50 Hz, 3-phase grid, driving a synchronous generator, is used for this application.
Which one of the following combinations is a suitable choice for the number of poles in the motor and generator, respectively?
(A)
2, 6
(B)
6, 2
(C)
4, 6
(D)
6, 4
Answer (official key): B
Worked solution: in your report after you take this paper.
Q21 · Electrical Machines · MCQ · 1 mark
Which one of the following options is correct regarding the typical double-squirrel-cage structure used in induction motors?
(A)
At starting, a larger portion of the rotor current flows in the outer cage
(B)
At starting, a larger portion of the rotor current flows in the inner cage
(C)
At rated speed, most of the rotor current flows in the outer cage
(D)
The purpose of the double-squirrel-cage structure is to lower the effective rotor resistance at starting
Answer (official key): A
Worked solution: in your report after you take this paper.
Q22 · Electrical Machines · MCQ · 1 mark
The figure shows the single-line diagram of a synchronous generator delivering P = 50 MW of power at unity power factor to an infinite bus.
Is denotes the stator current phasor. If the field excitation is increased, which one of the following options correctly describes its effect on the stator current, power factor, and load angle of the machine?
(A)
Stator current increases, power factor becomes lagging, load angle remains the same
(B)
Stator current decreases, power factor becomes leading, load angle remains the same
(C)
Stator current increases, power factor becomes lagging, load angle decreases
(D)
Stator current increases, power factor becomes leading, load angle increases
Answer (official key): C
Worked solution: in your report after you take this paper.
Q23 · Electric Circuits · MCQ · 1 mark
A circuit with ideal elements is shown.
Which one of the following options correctly identifies all the linear elements in the circuit?
(A)
R only
(B)
R, L, and C only
(C)
D only
(D)
L, C, and D only
Answer (official key): B
Worked solution: in your report after you take this paper.
Q24 · Electric Circuits · MCQ · 1 mark
For the circuit shown, which one of the following options correctly identifies the Thevenin’s equivalent parameters between nodes Y and Z?
(A)
VTH = 100 V, RTH = 10 kΩ
(B)
VTH = 140 V, RTH = 0 Ω
(C)
VTH = 100 V, RTH = 0 Ω
(D)
VTH = 140 V, RTH = 10 kΩ
Answer (official key): B
Worked solution: in your report after you take this paper.
Q25 · Electric Circuits · MCQ · 1 mark
Refer to the four circuits shown.
Which one of the following options for k1, k2, k3, and k4 makes all of them realizable?
(A)
k1=1, k4=−1/3, for all values of k2 and k3
(B)
k2=−2, k3=+1/3, for all values of k1 and k4
(C)
k1=2, k2=0.5, k3=−2/3, k4=−3
(D)
k1=2, k2=−0.5, k3=−2/3, k4=+3
Answer (official key): A
Worked solution: in your report after you take this paper.
Q26 · Electric Circuits · MCQ · 1 mark
A single-phase voltage source vs=325sin(2π50t) V delivers a current
i=12sin(2π50t)+9sin(2π150t)A
to a load.
The load power factor, correct up to two decimal places, is:
(A)
1.00
(B)
0.80
(C)
0.65
(D)
0.57
Answer (official key): B
Worked solution: in your report after you take this paper.
Q27 · Power Electronics · MCQ · 1 mark
The figure shows a straight-line approximation for the forward characteristics of a power diode. A continuous on-state current of 15 A is flowing through the diode.
What is the power loss in the diode?
(A)
32.8 W
(B)
21.2 W
(C)
18.6 W
(D)
23.1 W
Answer (official key): C
Worked solution: in your report after you take this paper.
Q28 · Power Electronics · MCQ · 1 mark
Consider the circuit shown in Figure (a). A gate pulse vg is applied between time instants t0 and t1. After t1, during the MOSFET turn OFF process, it experiences a voltage overshoot.
Based on the vds waveforms shown in Figure (b), which one of the following options is correct?
(A)
R1>R2>R3
(B)
R1>R3>R2
(C)
R3>R2>R1
(D)
R2>R3>R1
Answer (official key): B
Worked solution: in your report after you take this paper.
Q29 · Control Systems · MCQ · 1 mark
The asymptotic Bode magnitude plot of a system is shown.
Which one of the following options best represents the transfer function of the system?
(A)
G(s)=ω0s1+ω0s
(B)
G(s)=1+ω0sω0s
(C)
G(s)=1−ω0s1+ω0s
(D)
G(s)=1+ω0s1−ω0s
Answer (official key): A
Worked solution: in your report after you take this paper.
Q30 · Linear Algebra · MSQ · 1 mark
Two n×n matrices A and B have a common eigenvalue 2, and the same corresponding nonzero eigenvector.
Which of the following options is/are correct?
(Note: I is the n×n identity matrix.)
(A)
Determinant (A−2I)=0
(B)
Determinant (B−2I)=0
(C)
Determinant (A+B−2I)=0
(D)
Determinant (A+B−4I)=0
Answer (official key): A, B, D
Worked solution: in your report after you take this paper.
Q31 · Electrical Machines · MSQ · 1 mark
A 220V/12V single-phase transformer is designed for use in India and rated 100 VA at 50 Hz. Later, this unit is shipped to the USA where it is used as a 110V/6V transformer at 60 Hz.
Which of the following statements is/are correct?
(A)
No-load current drawn would be smaller for operation in the USA compared to that in India
(B)
For the same load current, the losses would be higher in the USA compared to that in India
(C)
The peak magnetic flux density in the core would be higher while operating in the USA compared to that in India
(D)
The eddy current losses in the core would be approximately 44% higher while operating in the USA compared to that in India
Given that F(x,y,z)=sin(y)x^+cos(x)y^+5z^, the integral
∬SF(x,y,z)⋅ds
over the unit sphere S centered at the origin evaluates to ________
(Round off to one decimal place)
Answer (official key): 0
Worked solution: in your report after you take this paper.
Q33 · Analog and Digital Electronics · Numerical · 1 mark
In the linear regulator circuit shown, the base to emitter voltage VBE of the BJT is 0.6 V. The Zener diode clamps the base voltage to 5.4 V. Ignore the biasing current of the Zener diode and BJT.
The maximum possible efficiency of the regulator circuit is ___________ %
(Round off to one decimal place)
Answer (official key): 47.5 to 48
Worked solution: in your report after you take this paper.
Q34 · Power Electronics · Numerical · 1 mark
Consider the circuit shown. Assume that the diode D is ideal. The supply voltage vs=325sin(2π50t) V, L=500 µH, and R=10Ω. The peak diode current (in amperes) is ______________
(Round off to one decimal place)
Answer (official key): 32.3 to 32.5
Worked solution: in your report after you take this paper.
Q35 · Linear Algebra · Numerical · 1 mark
A is an m×m skew-symmetric matrix with real-valued entries, and x is an m-dimensional column vector with real-valued entries such that xTx=1.
The quantity xTAx evaluates to _________
(Answer in integer)
Answer (official key): 0
Worked solution: in your report after you take this paper.
Q36 · Calculus · MCQ · 2 marks
A time-limited waveform g(x) is specified as follows:
g(x)=⎩⎨⎧−k,+k,0,−π<x≤00<x≤πotherwise
A new waveform f(x) is constructed from g(x) as follows:
f(x)=m=−∞∑∞g(x+2πm),for all x∈R
The sum of the coefficients of the third harmonics of the sine and cosine terms in the trigonometric Fourier series expansion of f(x) is 3π2.
What is the value of k?
(A)
1
(B)
21
(C)
31
(D)
41
Answer (official key): B
Worked solution: in your report after you take this paper.
Q37 · Analog and Digital Electronics · MCQ · 2 marks
In the circuit shown, the open loop gain of the operational amplifier is A0=105.
What is the voltage gain of the circuit?
(Round off to two decimal places)
(A)
–16.67
(B)
–20.00
(C)
–21.00
(D)
–12.67
Answer (official key): A
Worked solution: in your report after you take this paper.
Q38 · Electrical Machines · MCQ · 2 marks
Three single-phase 11 kV/3.3 kV transformers are connected to form a three-phase transformer bank with connections as shown.
Considering ABC phase sequence, the vector group of the transformer is:
(A)
Dd0
(B)
Dd4
(C)
Dd6
(D)
Dd10
Answer (official key): D
Worked solution: in your report after you take this paper.
Given that the CTs are ideal with no saturation, and the turns ratio of the Main CT is 300:5 and that of the Auxiliary Transformer (YnΔ) is 2:1 on every phase, the value of IˉRA, rounded off to three decimal places, is:
(A)
0 A
(B)
0.653∠17.556∘ A
(C)
537.240∠4.105∘ A
(D)
8.954∠4.105∘ A
Answer (official key): D
Worked solution: in your report after you take this paper.
Q40 · Power Systems · MCQ · 2 marks
The operating characteristic of a reactance relay is given by
X≤1,
where X is the reactance calculated by the relay. Its operating characteristic in the admittance plane (G–B plane, where G and B denote conductance and susceptance, respectively, expressed in ℧) is given by:
(A)
G2+(B+0.5)2=41
(B)
B≤1
(C)
G2+(B+1)2=21
(D)
G2+(B−1)2=21
Answer (official key): A
Worked solution: in your report after you take this paper.
Q41 · Power Systems · MCQ · 2 marks
A three-phase two-winding transformer has a voltage transformation ratio VSVP=0.866+j0.5, where VP is the primary side voltage in p.u., and VS is the secondary side voltage in p.u. IP and IS represent the currents injected into the primary and secondary sides of the transformer, respectively. The admittance corresponding to the leakage impedance of the transformer referred to the secondary is yt p.u. Neglect the magnetizing branch.
Q46 · Analog and Digital Electronics · MCQ · 2 marks
The MOSFET switches shown in the circuit are ideal.
Which of the following is the correct option for Boolean logical expression of the output (OUT), and the maximum possible power (P) consumed by the circuit?
Consider the single-phase voltage source inverter circuit feeding an inductive load (L). Assume that the power MOSFET switches are ideal. S1 and S2 are switched on during the first 10 µs, and S3 and S4 are switched on during the next 10 µs in a switching cycle. The switches in the same leg are thus switched in a complementary fashion. Neglect the dead time. The waveform of the inductor current (iL) in the steady state is triangular with a peak value of 5 A as shown.
The rms value of the current through the switch S1 is:
(A)
2.88 A
(B)
2.04 A
(C)
3.54 A
(D)
2.50 A
Answer (official key): B
Worked solution: in your report after you take this paper.
Q48 · Power Electronics · MCQ · 2 marks
Consider the boost converter circuit shown. Assume that the semiconductor devices are ideal. In steady state, the inductor current rises linearly from 0 A to 6 A in the first 10 µs and then falls linearly from 6 A to 0 A in the next 10 µs of every switching cycle as shown. The load resistance R is 10 Ω and the capacitance C is 500 µF.
Neglect the ripple in the output voltage. What is the input voltage Vdc?
(A)
10.0 V
(B)
15.0 V
(C)
7.5 V
(D)
12.5 V
Answer (official key): C
Worked solution: in your report after you take this paper.
Q49 · Linear Algebra · MCQ · 2 marks
Which one of the following statements is ALWAYS correct about a collection of p column vectors, each having n real-valued entries?
(A)
If p>n, then the column vectors must be linearly dependent
(B)
If p>n, then the column vectors must be linearly independent
(C)
If p=n, then the column vectors must be orthogonal
(D)
If p<n, then the column vectors must be linearly independent
Answer (official key): A
Worked solution: in your report after you take this paper.
Q50 · Differential Equations · MCQ · 2 marks
Consider the second-order differential equation
dx2d2y+dxdy+y=0
with initial conditions
y(0)=1,dxdyx=0=1
The solution is given by
(A)
y(x)=exp(−x/2)(cos(23x)+3sin(23x))
(B)
y(x)=exp(−x/2)(cos(23x)+31sin(23x))
(C)
y(x)=exp(−x/2)(cos(23x)−31sin(23x))
(D)
y(x)=exp(−x/2)(cos(23x)−3sin(23x))
Answer (official key): A
Worked solution: in your report after you take this paper.
Q51 · Electromagnetic Fields · MCQ · 2 marks
The figure shows an arbitrarily shaped planar conducting loop A in the XY plane. Two nonintersecting regions with areas a1 and a2 within the loop are subjected to magnetic fields
When the generators are operating at their optimal generation, meeting the total load requirement, the real power loss in the system is ____ MW
(Round off to one decimal place)
Consider the Lagrange multiplier λ=70.25 for optimal generation.
Answer (official key): Marks to all
Everyone who took this paper got the marks for this question. Marks to all in GATE
Worked solution: in your report after you take this paper.
Q59 · Electrical Machines · Numerical · 2 marks
A balanced three-phase supply is given to a 30 kW, 4-pole, 400 V, 50 Hz, wound rotor induction motor with Y-connected stator and rotor windings. The motor is driving a constant torque load. With shorted sliprings, the machine runs at 1476 rpm.
When an external non-inductive resistance of 0.27 Ω per phase is connected in series in the rotor circuit, the steady-state speed drops to 1404 rpm.
Neglecting rotational losses, the actual per phase rotor winding resistance is ____ Ω
(Round off to two decimal places)
Answer (official key): 0.09
Worked solution: in your report after you take this paper.
Q60 · Electric Circuits · Numerical · 2 marks
Consider the two-port network shown. For maximum power transfer to the resistive load (RL), the value of RL should be__________ Ω
Worked solution: in your report after you take this paper.
Q63 · Electromagnetic Fields · Numerical · 2 marks
A uniform spherical volume charge distribution of radius 2 m, centered at the origin, has a strength of π3×10−6 C/m³. A point charge of strength π×8.854×10−12 C is moved from (−3,0,−4) to (0,0,4) in Cartesian coordinate system. The relative permittivity of the medium is 1 and the coordinate values are in meters.
The work done during the process is ______ µJ
(Round off to two decimal places)
Answer (official key): 0.38 to 0.42
Worked solution: in your report after you take this paper.
Q64 · Probability and Statistics · Numerical · 2 marks
Let X and Y be two real-valued random variables with
E(X)=1,E(Y)=2,E(X2)=4,E(Y2)=9,E(XY)=0.9,
where E denotes the expectation operator.
The value of α that minimizes E[(X−αY)2] is __________
(Round off to one decimal place)
Answer (official key): 0.1
Worked solution: in your report after you take this paper.
Q65 · Calculus · Numerical · 2 marks
The integral
π1∫0∞(1+x2026)(1+x2)x2026dx
evaluates to _________
(Round off to two decimal places)
Answer (official key): 0.25
Worked solution: in your report after you take this paper.