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# (Paper) BSNL Telecom Technical Assistant (TTA) 2008 Model Question Papers

**Paper : BSNL Telecom Technical Assistant
(TTA) 2008 Model Question Papers**

1. If the matrix A = is singular, then ? =

a) 3 b) 4 c) 2 d) 5

2. A = is symmetric, then x =

a) 3 b) 4 c) 2 d) 5

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

a) 9 b) 6 c) 1 d) 27

4. If A = , then A-1 =

a) b) c) d)

5. If A = then A2 is equal to

a) A b) –A c) Null Matrix d) I

6. is a

a) rectangular matrix b) singular matrix

b) non-singular matrix d) skew-symmetric matrix

7. The slope of the straight line whose inclination with negative x-axis is 120º is

a) b) c) 1 d) infinity

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

a) m1 = m2 b) m1m2 = 0 c) m1m2 = -1 d) m1 + m2 = -1

9. The rate of increase of the radius of a circle is 1 cm/sec, the rate of increase of its area is 4? cm2/sec at a particular instant. The radius at that instant is

a) 2 cm b) 3 cm c) 4 cm d) 6 cm

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

a) 0.2 cm 2/min b) 0.4 cm 2/min c) 0.1 cm 2/min d) 0.6 cm 2/min

11.A particle is moving on a plane according to the distance-time relationship is given by s = t3 + 6t2 + 8t – 4. When its acceleration is 8 m/sec2, its velocity is

a) 8 m/sec b) 11 m/sec c) 23 m/sec d) -1 m/sec

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

a) 4 b) 64 c) 32 d) 96

13.The distance moved by a particle traveling in a straight line in t seconds is given by s = 45t + 11t2 – t3. The time taken by the particle to come to rest is

a) 9 sec b) 5 sec c) 3 sec d) 2 sec

14.The distance s described by a particle in time t is given by the relation s = aet + be-t. The acceleration is equal to

a) velocity b) the distance traveled

c) twice the distance traveled d) the square of the distance traveled

15.The slope of the normal to the curve y = at the point is

a) 9 b) -9 c) d)

17.The normal to the curve y = f(x) will be parallel to x-axis if

a) b) c) d)

18.The maximum point of the function 2×3 – 9×2 + 12x is

a) x = 0 b) x = 5 c) x = 1 d) x = 2

19.The minimum value of 2×3 – 9×2 + 12x – 4 is

a) 1 b) 3 c) 0 d) -2

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

a) (1,0) b) (1,1) c) (6,126) d) (-1,-7)

21.Velocity of sound is greatest in

a) Solids b) Liquids c) Gases d) None of these

22.If the phase difference between the two waves is 2? during superimposition, then the resultant amplitude is

a) Maximum b) Minimum c) Half of maximum d) None of these

23.If two waves of same frequency and same amplitude on superimposition produce a resultant disturbance of the same amplitude, the wave differ in phase by

a) b) c) d)

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

a) 400 cm/sec b) 300 cm/sec c) 200 cm/sec d) 100 cm/sec

25.Equation of a plane progressive wave is given by y = 0.2 cos ?(0.04t + 0.02x – 1/6). The distance is expressed in cm and time in sec. The minimum distance between two particles separated by phase difference ?/2 is radian is

a) 25 cm b) 12.5 cm c) 8 cm d) 4 cm

26.Ultrasonic waves are those waves which

a) Human being can hear b) Human being cannot hear

c) Have high velocity d) Have large amplitude

27.It is possible to distinguish between the transverse and longitudinal waves by studying the property of

a) Interference b) Polarization c) Diffraction d) Reflection

28.The following phenomenon cannot be observed for sound waves

a) Refraction b) Polarization c) Diffraction d) Reflection

29.Doppler shift in frequency does not depend upon

a) Frequency of the wave produced b) Velocity of the source

c) Velocity of the listener/observer d) Distance between source and listener

30.A source of sound of frequency 450 cycles/second is moving towards a stationary observer with 34 m/s speed. If the speed of sound is 340 m/s then the apparent frequency will be

a) 410 cps b) 550 cps c) 500 cps d) 450 cps

31.An observer moves towards a stationary source of sound of frequency n. The apparent frequency heard by him is 2n. If the velocity of sound in air is 332 m/s, then the velocity of observer is

a) 166 m/s b) 664 m/s c) 332 m/s d) 1328 m/s

32.The equation of a wave traveling in a string can be written as y = 3 cos ?(100t – x).Its wavelength is

a) 100 cm b) 5 cm c) 3 cm d) 2 cm

33.Sound velocity is maximum in

a) O2 b) H2 c) He d) N2

34.Phon is the unit of

a) Pitch b) Quality c) Timbre d) Loudness

35.Loudness of sound L and corresponding intensity of sound I are related as

a) L = KI2 b) L = KI c) L = K d) L = K log I

36.The index of refraction of a medium is 1.5. If the speed of light in air is 3 x 108 m/s, then its speed in the medium will be

a) 2 x 108 m/s b) 1.2 x 108 m/s c) 4 x 108 m/s d) 3.2 x 108 m/s

37.The ratio of intensities of the two waves is given by 4:1. The ratio of amplitudes of two waves is

a) 2:1 b) 1:2 c) 4:1 d) 1:4

38.Two source of waves are called coherent if

a) Both have the same amplitude by vibrations

b) Both produce waves of different wavelength having constant phase difference

c) Both produce waves of same wavelength having constant phase difference

d) Both produce waves having the same velocity

39.Which of the following does not support the wave nature of light?

a) Interference b) Diffraction c) Polarization d) Photoelectric effect

40.Velocity of light will be minimum in

a) Vacuum b) Air c) Water d) Glass

41.Wavelength of light of frequency 100 Hz is

a) 2 x 106 m/s b) 3 x 106 m/s c) 4 x 106 m/s d) 5 x 106 m/s

42.A rocket is going away from earth at a speed of 106 m/s. If the wavelength of the light wave emitted by it be 5700 Å, its Doppler’s shift will be

a) 200 Å b) 19 Å c) 20 Å d) 0.2 Å

43.Colour of light is known by its

a) Velocity b) Amplitude c) Frequency d) Polarization

44.A rocket is going away from the earth at a speed 0.2c where c = Speed of light. It emits a signal of frequency 4 x 107 Hz. The frequency observed by an observer on the earth will be

a) 4 x 106 Hz b) 3.3 x 106 Hz c) 3 x 106 Hz d) 5 x 107 Hz

45.A light wave has a frequency of 4 x 1014 Hz and a wavelength of 5 x 10-7 m in a medium. The refractive index of the medium is

a) 1.5 b) 1.33 c) 1.0 d) 0.66

46.Stars are twinkling due to optical phenomenon of

a) Refraction b) Scattering c) Reflection d) Diffraction

47.The splitting of white light into several colours on passing through a glass prism is due to

a) Refraction b) Reflection c) Interference d) Diffraction

48.In Bohr’s model, if the atomic radius of the first orbit is ro, then the radius of the fourth orbit is

a) 16 ro b) ro c) 4 ro d) ro/16

49.The average binding energy per nucleon in the nucleus of an atom is approximately

a) 8 eV b) 8 MeV c) 8 KeV d) 8 Volt

50.The mass equivalent of 931 MeV energy is

a) 1.66 x 10-20 kg b) 1.66 x 10-27 kg

c) 6.02 x 10-24 kg d) 6.02 x 10-27 kg