BSNL Question-Paper

                                                         BSNL Model Paper

1. Identify the correct match for the given transistor
a. Enhancement type P channel MOSFET
b. Depletion type N channel MOSFET
c. Enhancement type N channel MOSFET
d. Depletion type P channel MOSFET

2. In case a signal band limited to fm is sampled at a rate less than 2fm, the constructed signal will be
a. Distortion less
b. Small in amplitude
c. Having higher frequencies suppressed
d. Distorted

3. Quad 2 input AND gates IC No is
a. 7411
b. 7404
c. 7400
d. 7408

4. Registers in which data is entered or taken out in serial form are referred as
a. left shift register
b. right shift register
c. shift registers
d. none of the above

5. The expression ABC can be simplified to
Ans. A + B + C

6. An ideal power supply consist of
a. Very small output resistance
b. Zero internal resistance
c. Very large input resistance
d. Very large output resistance

7. The linearity error for a digital input is indicated by

8. Register and counters are similar in the sense that they both
a. count pulses
b. store binary operation
c. shift registers
d. made from an array of flip flops and
gates integrated on a single chip

9. In the 8421 BCD code the decimal number 125 is written as
a. 1111101
b. 0001 0010 0101
c. 7D
d. None of the above

10. In D/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of bits required is
a. 7
b. 8
c. 9
d. 200

11. On differentiation unit impulse function results in 
a. Unit parabolic function.
b. Unit triplet.
c. Unit doublet.
d. Unit ramp function.

12. Read the following;
i. Routh Hermitz's criterion is in time domain.
ii. Root locus plot is in time domain.
iii. Bode plot is in frequency domain.
iv. Nyquist criterion is in frequency domain.
a. 2, 3, and 4 are correct
b. 1, 2 and 3 are correct
c. 3 and 4 are correct
d. All four are correct.

13. The maximum phase shift that can be provided by a lead compensator with transferfunction.
a. 150
b. 450
c. 300
d. 600

14. The correct sequence of steps required to improve system stability is
a. Insert derivative action, use negative feedback, reduce gain.
b. Reduce gain, use negative feedback, insert derivative action.
c. Reduce gain, insert derivative action, use negative feedback.
d. Use negative feedback, reduce gain, insert derivative action.

15. Identity slope change at w = 10 of the magnitude v/s frequency characteristic of a unity feedback system with the following open-loop transfer function
a.-40dB/dec to-20dB/dec
b. 40dB/dec to 20dB/dec
c.-20dB/dec to-40dB/dec
d. 40dB/dec to-20dB/dec

16. In the feedback control system the loop transfer function is given by Number of asymptotes of its root loci is
a. 1
b. 2
c. 3
d. 4

17. In a closed - loop transfer function the imaginary axis intercepts of the root loci will be

18. Considering the following statement:In a magic tee
1. the collinear arms are isolated from each other
2. one of the collinear is isolated from the E-arm
3. one of the collinear arm is isolated from the H-arm
4. E-arm and H-arm are isolated from each other.
Of these statements
a. 1 and 2 are correct
b. 1 and 3 are correct
c. 1 and 4 are correct
d. 2 and 3 are correct

19. In 1965 first geostationary satellite was launched called
a. ANIK
b. EARLY BIRD (Intel sat-1)
c. WESTAR
d. MOLNIYA

20.--- watt of power is received from sun per m2 surface area of a geosynchronous satellite
a. 100
b. 500
c. 2000
d. 1000

21. The ripple factor in an LC filter
a. Increases with the load current
b. Increases with the load resistance
c. Remains constant with the load current
d. Has the lowest value

22. In different parts of the country identical telephone numbers are distinguished by their
a. Language digits
b. Access digits
c. Area codes
d. Central office codes

23. Amplitude modulation is used for broadcasting because
a. it is move noise immune than other modulation systems
b. compared with other systems it requires less transmitting power
c. its use avoids receiver complexity
d. no other modulation system can provide the necessary bandwidth for high fidelity

84. The amplifiers following the modulated stage in a low level modulation AM system be
a. linear amplifier
b. harmonic generators
c. class C power amplifiers
d. class B untuned amplifiers

25. In a radar system maximum unambiguous range depends on
a. maximum power of the transmitter
b. pulse repetition frequency
c. width of the transmitted pulse
d. sensitivity of the radar receiver

26. In composite video waveform the function of the serrations, is to
a. equalize the charge in the integrator before the start of vertical retrace.
b. help vertical synchronization
c. help horizontal synchronization.
d. simplify the generation of the vertical sync pulse

27. The frequency range 30MHz- 300MHz is
a. medium frequency
b. very high frequency
c. super high frequency
d. Infrared frequency

28.Which wave cannot exist inside wave guide
a. TE
b. TM
c. TEM
d. HE

29. Ionosphere layer of earth is situated at
a. upto 18kms from earth
b. from 18 to 70 km
c. 70 to 500 km
d. above 500 km

30. A two cavity klystron tube is a
a. velocity modulated tube
b. frequency modulated tube
c. Amplitude modulated tube
d. simple triode