GATE 2007 EC Question Paper

GATE 2007 ECE Question Paper

Q.1 – Q.20 Carry One Mark Each
Q.21 – Q.75 Carry Two Marks Each
Linked Answer Questions: Q.76 to Q.85 Carry Two Marks Each

10. In a P+ n junction diode under reverse bias, the magnitude of electric field is maximum at
(A) the edge of the depletion region on the p-side
(B) the edge of the depletion region on the n-side
(C) the p+ n junction
(D) the centre of the depletion region on the n-side

12. In a transconductance amplifier, it is desirable to have
(A) a large input resistance and a large output resistance
(B) a large input resistance and a small output resistance
(C) a small input resistance and a large output resistance
(D) a small input resistance and a small output resistance
13. X = 01110 and Y = 11001 are two 5-bit binary numbers represented in two’s
complement format. The sum of X and Y represented in two’s complement format
using 6 bits is:
(A) 100111 (B) 001000 (C) 000111 (D) 101001
14. The Boolean function Y AB CD = + is to be realized using only 2-input NAND
gates. The minimum number of gates required is:
(A) 2 (B) 3 (C) 4 (D) 5

21. It is given that X1,X2,.... Xm are M non-zero, orthogonal vectors. The dimension of the vector space spanned by the 2M vectors X1, X2.... Xm,-X1,-X2,...-Xm is:
(A) 2M (B) M + 1 (C) M
(D) dependent on the choice of X1,X2,... Xm

22. Consider the function F(x)=X2-X-2 The maximum value of f x( ) in the closed
interval [−4, 4] is:
(A) 18 (B) 10
(C) -2.25 (D) indeterminate

23. An examination consists of two papers, Paper 1 and Paper 2. The probability of
failing in Paper 1 is 0.3 and that in Paper 2 is 0.2. Given that a student has failed in Paper 2, the probability of failing in Paper 1 is 0.6. The probability of a student failing in both the papers is:
(A) 0.5 (B) 0.18 (C) 0.12 (D) 0.06

33. Group I lists four types of p-n junction diodes. Match each device in Group I with
one of the option in Group II to indicate the bias condition of that device in its
normal mode of operation.
Group I Group II
(P) Zener Diode (1) Forward bias
(Q) Solar cell (2) Reverse bias
(R) LASER diode
(S) Avalanche Photodiode
(A) P-1 Q-2 R-1 S-2 (B) P-2 Q-1 R-1 S-2
(C) P-2 Q-2 R-1 S-1 (D) P-2 Q-1 R-2 S-2

34. The DC current gain ( β ) of a BJT is 50. Assuming that the emitter injection
efficiency is 0.995, the base transport factor is:
(A) 0.980 (B) 0.985 (C) 0.990 (D) 0.995

35. Group I lists four different semiconductor devices. Match each device in Group I
with its characteristic property in Group II.
Group I Group II
(P) BJT (1) Population inversion
(Q) MOS capacitor (2) Pinch-off voltage
(R) LASER diode (3) Early effect
(S) JFET (4) Flat-band voltage
(A) P-3 Q-1 R-4 S-2 (B) P-1 Q-4 R-3 S-2
(C) P-3 Q-4 R-1 S-2 (D) P-3 Q-2 R-1 S-4

48. A Hilbert transformer is a
(A) non-linear system (B) non-causal system
(C) time-varying system (D) low-pass system

58. In delta modulation, the slope overload distortion can be reduced by
(A) decreasing the step size (B) decreasing the granular noise
(C) decreasing the sampling rate (D) increasing the step size

62. In a GSM system, 8 channels can co-exist in 200 KHz bandwidth using TDMA. A
GSM based cellular operator is allocated 5 MHz bandwidth. Assuming a frequency
reuse factor of 1/5 i.e. a five-cell repeat pattern, the maximum number of
simultaneous channels that can exist in one cell is:
(A) 200 (B) 40 (C) 25 (D) 5

64. An air-filled rectangular waveguide has inner dimensions of 3 cm × 2 cm. The
wave impedance of the TE20 mode of propagation in the waveguide at a frequency of 30 GHz is (free space impedance η0= Ω 377 )
(A) 308 Ω (B) 355 Ω (C) 400 Ω (D) 461 Ω

71. The gate oxide thickness in the MOS capacitor is:
(A) 50 nm (B) 143 nm (C) 350 nm (D) 1 µm

72. The maximum depletion layer width in silicon is
(A) 0.143 µm (B) 0.857 µm (C) 1 µm (D) 1.143 µm

73. Consider the following statements about the C-V characteristics plot:
S1: The MOS capacitor has an n-type substrate.
S2: If positive charges are introduced in the oxide, the C-V plot will shift to the
left. Then which of the following is true?
(A) Both S1 and S2 are true (B) S1 is true and S2 is false
(C) S1 is false and S2 is true (D) Both S1 and S2 are false

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