GATE 2024 EC question paper PDF and answer key

The official GATE 2024 Electronics & Communication Engineering paper, organised by IISc Bengaluru: 65 questions for 100 marks in 3 hours. Download the official question paper and answer key as PDFs. Below is how the marks were split by topic, the complete official answer key and 5 questions solved step by step.

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Question paper (PDF)Official answer key (PDF)

Source: the official paper and answer key published by IISc Bengaluru for GATE 2024 (official GATE site). Spotted a mistake? Email team@lemyte.com.

General Aptitude: 10 · 15 marks
Electronics & Communication Engineering: 55 · 85 marks
MCQ / MSQ / NAT: 39 / 8 / 18
Marks to all: Q 14, 44, 48

Where the marks were

GATE 2024 EC topic-wise marks

Electronics & Communication Engineering questions only; General Aptitude adds 15 marks on top. The top three topics carried 39 of the 85 subject marks.

Topic	Questions	Marks
Networks, Signals and Systems	10	16
Electronic Devices	7	12
Digital Circuits	7	11
Communications	7	10
Analog Circuits	7	10
Control Systems	5	8
Electromagnetics	4	6
Calculus	3	5
Linear Algebra	2	3
Complex Variables	1	2
Differential Equations	1	1
Probability and Statistics	1	1

Free solved questions

5 solved questions from GATE 2024 EC

Question text and figures as in the official paper, the answer from the official key, and a worked solution. The other 60 solutions are in your report after you take the paper.

Q2 · General Aptitude · MCQ · 1 mark

P, Q, R, S, and T have launched a new startup. Two of them are siblings. The office of the startup has just three rooms. All of them agree that the siblings should not share the same room.

If S and Q are single children, and the room allocations shown below are acceptable to all,

Figure for GATE 2024 EC question 2 (Analytical Aptitude)

then, which one of the given options is the siblings?

(A)
P and T
(B)
P and S
(C)
T and Q
(D)
T and R

Answer (official key): A

Solution

S and Q are single children, so the siblings are two of P, R and T. The pairs sharing a room cannot be siblings: P–R (first allocation) and R–T (second allocation). The only remaining pair is P and T.

Q10 · General Aptitude · MCQ · 2 marks

Two identical sheets A and B, of dimensions 24 cm × 16 cm, can be folded into half using two distinct operations, FO1 or FO2.

In FO1, the axis of folding remains parallel to the initial long edge, and in FO2, the axis of folding remains parallel to the initial short edge.

If sheet A is folded twice using FO1, and sheet B is folded twice using FO2, the ratio of the perimeters of the final shapes of A and B is

(A)
14:11
(B)
11:14
(C)
18:11
(D)
11:18

Answer (official key): A

Solution

FO1 halves the short side twice: $24 \times 16 \to 24 \times 8 \to 24 \times 4$ , perimeter 56 cm.
FO2 halves the long side twice: $24 \times 16 \to 12 \times 16 \to 6 \times 16$ , perimeter 44 cm.

The ratio is $56:44 = 14:11$ .

Q49 · Analog Circuits · MCQ · 2 marks

The opamps in the circuit shown are ideal, but have saturation voltages of ±10 V.

Figure for GATE 2024 EC question 49 (Analog Circuits)

Assume that the initial inductor current is 0 A. The input voltage ( $V_i$ ) is a triangular signal with peak voltages of ±2 V and time period of 8 µs. Which one of the following statements is true?

(A)
$V_{01}$ is delayed by 2 µs relative to $V_i$ , and $V_{02}$ is a triangular waveform.
(B)
$V_{01}$ is not delayed relative to $V_i$ , and $V_{02}$ is a trapezoidal waveform.
(C)
$V_{01}$ is not delayed relative to $V_i$ , and $V_{02}$ is a triangular waveform.
(D)
$V_{01}$ is delayed by 1 µs relative to $V_i$ , and $V_{02}$ is a trapezoidal waveform.

Answer (official key): D

Solution

OPA1 is a non-inverting Schmitt trigger with thresholds $\pm 10 \times \frac{10\text{k}}{100\text{k}} = \pm 1$ V. The input slope is $\frac{4\text{ V}}{4\ \mu\text{s}} = 1$ V/µs, so after each zero crossing it takes 1 µs to reach $\pm 1$ V. $V_{01}$ is therefore a ±10 V square wave delayed by 1 µs.

OPA2 with the series inductor integrates: $\frac{dV_{02}}{dt} = -\frac{R}{L}V_{01} = \mp 10^7$ V/s $= \mp 10$ V/µs. It reaches ±10 V saturation in 2 µs of each 4 µs half-period, then holds, giving a trapezoidal waveform.

Q52 · Electronic Devices · MSQ · 2 marks

Which of the following statements is/are true for a BJT with respect to its DC current gain $\beta$ ?

(A)
Under high-level injection condition in forward active mode, $\beta$ will decrease with increase in the magnitude of collector current.
(B)
Under low-level injection condition in forward active mode, where the current at the emitter-base junction is dominated by recombination-generation process, $\beta$ will decrease with increase in the magnitude of collector current.
(C)
$\beta$ will be lower when the BJT is in saturation region compared to when it is in active region.
(D)
A higher value of $\beta$ will lead to a lower value of the collector-to-emitter breakdown voltage.

Answer (official key): A, C, D

Solution

(A) True: high-level injection reduces emitter efficiency, so $\beta$ falls at high $I_C$ .
(B) False: in the recombination-dominated low-current region, $\beta$ increases with $I_C$ .
(C) True: in saturation, $I_C/I_B$ is forced below its active-region value.
(D) True: $BV_{CEO} \approx BV_{CBO}/\beta^{1/n}$ , so a higher $\beta$ gives a lower breakdown voltage.

Q57 · Communications · Numerical · 2 marks

Let $X(t) = A\cos(2\pi f_0t + \theta)$ be a random process, where amplitude $A$ and phase $\theta$ are independent of each other, and are uniformly distributed in the intervals $[-2, 2]$ and $[0, 2\pi]$ , respectively. $X(t)$ is fed to an 8-bit uniform mid-rise type quantizer. Given that the autocorrelation of $X(t)$ is $R_X(\tau) = \frac{2}{3}\cos(2\pi f_0\tau)$ , the signal to quantization noise ratio (in dB, rounded off to two decimal places) at the output of the quantizer is __________.

Answer (official key): 45 to 45.3

Solution

Signal power is $R_X(0) = \frac{2}{3}$ . The quantizer covers $[-2, 2]$ with $2^8$ levels, so $\Delta = \frac{4}{256} = \frac{1}{64}$ and the noise power is $\frac{\Delta^2}{12} = \frac{1}{49152}$ . $\text{SQNR} = \frac{2/3}{1/49152} = 32768 \Rightarrow 45.15\ \text{dB}$

The other 60 questions are solved in your report when you take GATE 2024 EC as a 3-hour test.

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Official answer key

GATE 2024 EC answer key

All 65 answers from the official key. Numerical answers are ranges; “or” means the key accepts either answer.

Download the official GATE 2024 EC answer key (PDF)

Q	Topic	Type	Marks	Answer
1	Verbal Aptitude	MCQ	1	A
2	Analytical Aptitude	MCQ	1	A
3	Quantitative Aptitude	MCQ	1	B
4	Quantitative Aptitude	MCQ	1	C
5	Quantitative Aptitude	MCQ	1	A
6	Verbal Aptitude	MCQ	2	C
7	Spatial Aptitude	MCQ	2	D
8	Analytical Aptitude	MCQ	2	C
9	Spatial Aptitude	MCQ	2	A
10	Analytical Aptitude	MCQ	2	A
11	Differential Equations	MCQ	1	A
12	Control Systems	MCQ	1	A
13	Control Systems	MCQ	1	D
14	Communications	MCQ	1	Marks to all
15	Electromagnetics	MCQ	1	A
16	Electromagnetics	MCQ	1	B
17	Analog Circuits	MCQ	1	A
18	Analog Circuits	MCQ	1	A
19	Digital Circuits	MCQ	1	A
20	Communications	MCQ	1	A
21	Networks, Signals and Systems	MCQ	1	A
22	Electronic Devices	MCQ	1	A
23	Analog Circuits	MCQ	1	A
24	Networks, Signals and Systems	MSQ	1	A, C, D
25	Calculus	MSQ	1	A, C
26	Electronic Devices	MSQ	1	A, B, C
27	Digital Circuits	Numerical	1	2047
28	Communications	Numerical	1	2.49 to 2.51
29	Digital Circuits	Numerical	1	11
30	Linear Algebra	Numerical	1	5
31	Networks, Signals and Systems	Numerical	1	2
32	Networks, Signals and Systems	Numerical	1	0.75
33	Probability and Statistics	Numerical	1	0.5
34	Communications	Numerical	1	4
35	Analog Circuits	Numerical	1	0.25
36	Calculus	MCQ	2	A
37	Control Systems	MCQ	2	A
38	Control Systems	MCQ	2	B
39	Electromagnetics	MCQ	2	A
40	Digital Circuits	MCQ	2	B
41	Digital Circuits	MCQ	2	B
42	Digital Circuits	MCQ	2	B
43	Complex Variables	MCQ	2	D
44	Networks, Signals and Systems	MCQ	2	Marks to all
45	Communications	MCQ	2	B
46	Digital Circuits	MCQ	2	B
47	Communications	MCQ	2	A
48	Networks, Signals and Systems	MCQ	2	Marks to all
49	Analog Circuits	MCQ	2	D
50	Analog Circuits	MCQ	2	B
51	Analog Circuits	MCQ	2	B
52	Electronic Devices	MSQ	2	A, C, D
53	Control Systems	MSQ	2	A, C
54	Calculus	MSQ	2	A, B, D
55	Linear Algebra	MSQ	2	A, B
56	Networks, Signals and Systems	MSQ	2	A, D or A, C, D
57	Communications	Numerical	2	45 to 45.3
58	Electromagnetics	Numerical	2	200
59	Networks, Signals and Systems	Numerical	2	112
60	Networks, Signals and Systems	Numerical	2	1.5
61	Electronic Devices	Numerical	2	4.1 to 4.5
62	Networks, Signals and Systems	Numerical	2	2.5
63	Electronic Devices	Numerical	2	0.17 to 0.19
64	Electronic Devices	Numerical	2	52.4 to 52.6
65	Electronic Devices	Numerical	2	4 to 4.26

Questions about GATE 2024 EC

How many questions are in the GATE 2024 EC paper?

65 questions for 100 marks: 10 General Aptitude questions worth 15 marks and 55 Electronics & Communication Engineering questions worth 85 marks. By type, there were 39 MCQs, 8 MSQs, 18 numerical answer (NAT) questions. The paper lasted 3 hours.

Is there negative marking in GATE 2024 EC?

Yes, for MCQs only. A wrong MCQ answer costs one-third of its marks (−⅓ for a 1-mark question, −⅔ for a 2-mark question). MSQ and numerical (NAT) questions have no negative marking, and an MSQ earns marks only when every correct option is chosen.

Which topics carried the most marks in GATE 2024 EC?

Outside General Aptitude, the biggest topics were Networks, Signals and Systems (16 marks), Electronic Devices (12 marks), Digital Circuits (11 marks). The full topic-wise split is in the table on this page.

Were any GATE 2024 EC questions awarded marks to all?

Yes. The official key awarded full marks to everyone for questions 14, 44, 48.

Where does this GATE 2024 EC answer key come from?

From the official answer key published by IISc Bengaluru, which organised GATE 2024. Range answers for numerical questions and questions with more than one accepted answer are kept exactly as the key gives them.

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GATE 2024 EC question paper PDF and answer key

GATE 2024 EC topic-wise marks

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GATE 2024 EC answer key

Questions about GATE 2024 EC

How many questions are in the GATE 2024 EC paper?

Is there negative marking in GATE 2024 EC?

Which topics carried the most marks in GATE 2024 EC?

Were any GATE 2024 EC questions awarded marks to all?

Where does this GATE 2024 EC answer key come from?

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