bsnl tta.pdf

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BSNL TTA MODEL PAPER BASED ON PREVIOUS QUESTIONS

1.The most common modulation system used for telegraphy is

A. FSKB. PSK.C. PCMD. single tone modulationE. Two tone modulation

2. Which of these normally used household electrical bulbs will be having maximum

resistance.

A. 100 Watt bulb

B. 50 Watt bulbC. 200 Watt bulb

D. 25 Watt bulb

3. The ratio of the specific charge of an electron to that of a positron is

A. 1:1

B. 1:2

C. 2:1

D. 4:1.

4. . Attenuators have applications A. in AC circuits onlyB. in DC circuits onlyC. in AC as well DC circuitsD. in low frequency circuits only

5. When a source is delivering maximum power to load, the efficiency of the circuit isalways A. 50%B. 75%

C. 100%D. None of above

6. Two resistances are connected in parallel and each dissipates 50 waits. The totalpower supplied by the source is A. 25 wattsB. 50 wattsC. 100 watts




D. 200 watts

7. The main advantage of PCM system is: A. lower bandwidthB. lower power

C. lower noiseD. None

8. Easily adjustable tuning component in a waveguide is plunger

A. plunger and stubB. screwC. both (a) and (c)D. both (b) and (c)

9. Which of the following is not a microwave generation source?

A. KlystronB. MagnetronC. TWTD. Diode

10. VSB is an abbreviation of vestigal sideband, is derived by filtering

A. DSBB. AM

C. either (a) or (b)D. PM

11. FM broadcast band lies in

A. VHFB. UHFC. SHFD. HF

12.The modulation system inherently is most noise resistant in

A. SSB suppressed carrier B. FMC. PPMD. PCM

13. An FM transmitter has maximum frequency deviation of 75 KHz and reproducesaudio signal up to 15 KHz. Minimum channel width required, in KHz is






D. Infinity

20. In FM, the noise can be further decreased by

A. decreasing deviation

B. increasing deviationC. (c) keeping deviation constantD. (d) none of these

21. If A is a 3 x 3 matrix and det(3 A) = k det(A) then k =

A. 9B. 6C. 1D. 27

22. If two lines whose slopes are m1 and m2 are perpendicular iff

A. m1 = m2B. m1m2 = 0C. m1m2 = -1D. m1 + m2 = -1

23.If the side of a square is increasing at the rate of 0.02 cm/min, the rate at which itsarea is increasing at the instant when the length of the side is 5 cm is

A. 0.2 cm 2/minB. 0.4 cm 2/minC. 0.1 cm 2/minD. 0.6 cm 2/min

24. A stone moves vertically upwards according to the distance-time equation s = 16t – 2t2.The greatest height reached by the stone is

A. 4B. 64C. 32D. 96

25. The point of inflection of the function x3 - 3×2 + 3x is

A. (1,0)

B. (1,1)

C. (6,126)




D. (-1,-7)

26. The equation of a plane progressive wave is given by y = 2sin?(0.5x – 200t) where xand y are expressed in cm and t in sec. The wave velocity is

A. 400 cm/secB. 300 cm/secC. 200 cm/secD. 100 cm/sec

27. The following phenomenon cannot be observed for sound waves

A. RefractionB. PolarizationC. DiffractionD. Reflection

28. Sound velocity is maximum in

A. O2B. H2C. HeD. N2

29. Velocity of light will be minimum in

A. a) VacuumB. b) Air C. c) WaterD. d) Glass

30. The energy required to remove an electron in a hydrogen atom from n = 10 state is

A. 136.0 eVB. 13.60 eV

C. 1.36 eVD. 0.136 eV

31. Which is not a TWT slow wave structure

A. Coupled cavityB. helixC. ring bars




D. periodic permanent magnet

32. Which of these represent two parallel lines:

(a) Y - 4X - 4 = 0

(b) Y + AX - 4 = 0

(c) Y - 4X - 1 =0

A. (i) and (ii)

B. (i) and (iii)

C. (ii) and (iii)

D. (d) None of these

33. The slope of the line passing from points (7, 3) and (5, 1) is

A. 1

B. 2

C. 3

D. 4

34. During charging of a lead acid cell, the specific gravity of electrolyte will

A. Increase

B. Decrease

C. Remain constant

D. Increase then Decrease

35. What is the value of current that will flow when a p. d. 200 V is applied across a

circuit of 50 O resistance?

A. 4 A

B. 0.4 A

C. 10 A

D. 1 A

36. A Zener diode is

A. Forward biased heavily doped silicon p-n junction

B. Reversed biased heavily doped silicon p-n junction

C. Forward biased diode operating at breakdown point




D. Is used as rectifying device

37.. Which of these cannot store energy?

A. Capacitor

B. Inductor

C. Resistance

D. LC circuit.

38. The permeability of a material is 0.998. It is:

A. Diamagnetic

B. Paramagnetic

C. Ferromagnetic

D. (d) Anti ferromagnetic

39. In a common collector circuit, input resistance is:

A. Very high

B. Very low

C. Zero

D. Moderate.

40. Combined inductance of two inductors L1 and L2 connected and voltages areinterchanged

A. L1 + L2B. (L1 + L2)/ L1C. (L1 + L2) / (L1 X L2)D. (L1 X L2) / (L1 + L2)

41. The kirchoff's law fail in

A. Linear circuitsB. Non-linear circuitsC. Lumped parameter circuits

D. Distributed parameter circuits

42. A cascade connection of low pass filter and high pass filter is called

A. Band pass filter B. Band elimination filter C. Neither (a) nor (b)D. Both (a) and (b)




43. E.M. Waves of UHF is propagated efficiently via

A. parallel wire transmission linesB. open wire transmission lines

C. wave guidesD. (d) coaxial cables

44.In high power AM transmission, modulation is done at

A. Buffer stageB. Oscillator stageC. RF power stageD. If stage

45. Maximum undistorted power output of a transmitter is obtained when its modulationis:

A. more than 100%B. 100%C. less than 100%D. 50%

46. A Square matrix each of whose diagonal element is 1 and each of the non-diagonalelement is zero is called

A. Null matrix

B. Unit matrix

C. Diagonal matrix

D. Orthogonal matrix

47. Crystal oscillator is used when frequency required is

A. High

B. Low

C. Constant

D. Varying.

48. The response of a network is decided by the location of

A. Its polesB. Its zerosC. Either (a) nor (b)D. Both (a) and (b)



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