# Bhabha Atomic Research Center previous years question papers

BARC Bhabha Atomic Research Center previous years question papers of electronics and electrical BARC Aptitude question papers, BARC placement papers questions

BARC Bhabha Atomic Research Center Electronics and electrical technical questions of BARC placement papers

1 Consider a transmission line of characteristic impedance 50 ohms and the line is terminated at one end by +j50 ohms, the VSWR produced in the transmission line will be
(A) +1
(B)zero
(C)infinity
(D)-1

2 In a certain medium E = 10 Cos(108t–3y) a xV/m. What type of medium is it?
(A) Free space
(B)Lossy dielectric
(C)Lossless dielectric
(D)Perfect conductor

3 If D⋅∇=∈∇.Eand∇.J = σ∇.Ein a given material, the material is said to be
(A) Linear
(B)Homogeneous
(C) Isotropic
(D) Linear & Homogeneous

4 For a 300 Ω antenna operating with 5A of current, the radiated power is
(A) 7500 W
(B) 750 W
(C)75 W
(D)7500 mW

5. An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a frequency of 1MHZ is
(a) 10 volts
(b) 15 volts
(c) 5/3 vo lts
(d)5/2 volts

6 The early effect in a bipolar junction transistor is caused by
(a) fast turn-on
(b)fast turn-off
(c) large collector-base reverse bias
(d) large emitter-base forward bias

7 MOSFET can be used as a
(a) current controlled capacitor
(b) voltage controlled capacitor
(c) current controlled inductor
(d) voltage controlled inductors

8 An AM signal is detected using an envelop detector. The carrier frequency and modulating signal frequency are 1MHz and 2 kHz respectively. An appropriate value for the time constant of the envelope
detector is.
(A) 500 μsec
(B) 20 μsec
(C) 0.2 μsec
(D) 1μ sec

9 An AM modulator has output x(t)=A cos400 πt+Bcos 380 πt +Bcos420πt and The carrier power is 100 W and the efficiency is 40%. The value of A and B are
(A) 14.14, 8.16
(B) 50, 10
(C) 22.36, 13.46
(D) None of the above

10 A super heterodyne receiver is designed to receive transmitted signals between 5 and 10 MHz. High-side tuning is to be used. The tuning range of the local oscillator for IF frequency 500 kHz would be
(A) 4.5 MHz-9.5 MHz
(B) 5.5 MHz-10.5 MHz
(C) 4.5 MHz-10.5 MHz
(D) none of these

11 An analog signal is sampled at 36 kHz and quantized into 256 levels.The time duration of a bit of the binary coded signal is
(A) 5.78μs
(B) 3.47μs
(C) 6.43 ms
(D) 7.86 ms

12 The minimum sampling frequency (in samples/sec) required to reconstruct the following signal form its samples without distortion would be x(t)= 5(sin2 π 1000t/πt)3 +7(sin 2πt 1000t/πt)2
(A)2×103
(B)4×103
(C) 6×103
(D) 8×103

13 Three identical amplifier, each having a spot effective input noise temperature of 125 K and available power G are cascaded. The overall spot effective input noise temperature of the cascade is 155 K. The Gis
(A) 3
(B) 5
(C) 7
(D) 9

14 In the Op-Amp circuit shown, assume that the diode current follows the equation I=I s exp(V/Vt) Vi=2V , Vo=V01and for Vi=4V , Vo=V02The relationship between V01andV02is

15 The counter shown in fig. below is a

(A) MOD–8 up counter
(B) MOD–8 down counter
(C) MOD–6 up counter
(D) MOD–6 down counter

16 The MUX shown in fig. multiplexer. The output Z is

(A) A xor C
(B) A and C
(C) B xor C
(D) B and C