TANCET 2012 EEEIE

2012 PART 06 – ELECTRICAL, ELECTRONICS AND INSTRUMENTATION ENGINEERING (Answer ALL questions) 76.. 76

1) 2) 3) 4)

Two point point chang changes es Q and –Q are are locate located d on two opposite corners of a square as shown. If  the potential of the corner A is taken as 1V, then the potential at B, the centre of the square will be

77.. 77

1) zero

2)

3) 1 V

4)

1 2

80.. 80

The full full load load torque torque of a 3 phase 400V, 4 pole pole 50Hz induction motor is 48 Nm. The motor draws a phase current of 6.61A. The rotor resistance per phase referred to stator is 5 Ω . Neglecting magnetising reactance, the rotor speed at full load is 1) 1370 rpm 2) 1200 rpm 3) 1270 rpm 4) 1400 rpm

81.. 81

A 25 Hz, 120/3 120/30, 0, 500 500 VA VA transformer transformer is to be used on a 60 Hz source. If the core flux density is to remain unchanged, the maximum permissible primary voltage, the rated secondary voltage and the rated secondary current are, 1) 50 V, 12 12.5 V. 20 20 A 2) 288 V, 72 72 V, 6. 6.94 A  3) 288 V, 72 V, 16.67 16.67 A 4) 288 V, 72 V, 20 A 

V

2C

Which Whi ch one one of the the follow following ing sets sets of equa equatio tions ns is independent in Maxwell’s equations

1) the two curl equa equation tionss 2) the two two diverg divergence ence equat equations ions 3) both the the curl and divergen divergence ce equations equations

82. An indust industria riall consum consumer er has a dail daily y load load patter pattern n of 2000 kW, 0.8 lag of 12 hrs and 1000 kW UPF for 12 hrs. The load facto r is 1) 0.5 2) 0.75 3) 0.6 4) 2.0

4) the two curl equation equationss combined combined with the continuity equations 78.. 78

equal to source equal source imped impedenc ence e equal to to half of the the source source impedance impedance equa eq uall to ze zero ro equall to twice the equa the source source impedanc impedance e

Consid Con sider er the the voltag voltage e wavefo waveform rm shown shown in in the  figure.  figu re. The equatio equ ation n for V(t) is

1) 2) 3) 4) 79.. 79

u(t–1)+u( u(t–1) +u(t–2 t–2)+u )+u(t– (t–3) 3) u(t–1)+2u( u(t–1 )+2u(t–2)+ t–2)+3u(t– 3u(t–3) 3) u(t)+u(t–1) u(t)+ u(t–1)+u(t– +u(t–2)+u( 2)+u(t–4) t–4) u(t–1)+u(t–2 u(t–1) +u(t–2)+u(t )+u(t–3)–3u –3)–3u(t–4) (t–4)

Maximum Maximu m power power is transf transferr erred ed when when the load load impedance is

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83.. 83

A 100 km long long trans transmis missio sion n line line is loade loaded d at 110 kV. kV. If the loss of line is 5 MW and the load is 150 MVA, the resistance of the line is 1) 8. 8.06 06 oh ohms ms pe perr pha phase se 2) 0. 0.80 806 6 ohm ohmss per per ph phas ase e 3) 0. 0.08 0806 06 oh ohms ms pe perr pha phase se 4) 80.6 ohms ohms per per phase

84.. 84

At a parti particul cular ar unbal unbalanc anced ed node, node, the the real powers specified are leaving the node 20 MW MW,, 35 MW enteri ng the node 6 0 MW, MW, 30 MW the balanced power will be 1) 30 MW MW leavin leaving g the the node node 2) 45 MW MW leavin leaving g the the node node 3) 45 MW MW enteri entering ng the the node node 4) 22.5 MW enterin entering g and 22.5 MW leavin leaving g the node ME - ELECTRICAL , ELECTRONIC S AND INSTRUMENTATION ENGG ENGG.. - 2012

85. Load frequency control is achieved by properly matching the individual machine’s 1) Reactive powers 2) Generated voltages 3) Turbine inputs 4) Turbine and generator ratings 86.

90.

Junction capacitance is related with barrier potential as 1) C = kV–1/2 2) C = kV 1/2 3) C = kV 4) C = k/V

91.

If the maximum power rating of a transistor is 1 Watt and the collector current is 100 mA, then the maximum allowable collector voltage is 1) 0.1 V 2) 3 V 3) 10 V 4) 100 V

92.

The feedback resistance rd in small signal model of MOSFET is of the order of  1) 1 MΩ 2) 1000 MΩ 3) 1 KΩ   4) 100 Ω

93.

In 8085, to disable the whole interrupt system (except TRAP) 1) the DI instruction may be used 2) the DO instruction may be used 3) the INTERRUPT instruction may be used 4) the EI instruction may be used

94.

Which one of the following is equivalent to AND-OR realisation? 1) NAND-NOR realisation 2) NOR-NOR realisation 3) NOR-NAND realisation 4) NAND-NAND realisation

95.

A bit synchronous counter uses flip-flops with propagation delay time of 25 ns each. The maximum possible time required for change of  state will be 1) 15 ns 2) 30 ns 3) 45 ns 4) 60 ns

96.

The address bus of INTEL 8085 is 16 bit wide and hence the memory which can be accessed by this address bus is 1) 2 K bytes 2) 4 K bytes 3) 10 K bytes 4) 64 K bytes

97.

The number of multiplications needed to compute a 32 point DFT using radix-2 FFT  algorithm is 1) 80 2) 60 3) 40 4) 20

The transfer function of a multi-input multi output system with the state-space

 =AX+BU , Y=CX+DU representation of  X where X represents at state, Y the output and U the input vector, will be given by

87.

1) C(sI–A)–1

2) C(sI–A)–1+D

3) (sI–A)–1 B+D

4) dC(sI–A) –1B

A linear time system is described by the state  variable model

 x1   −1  x  =  0  2  y

=

0   x 1 

0  +      u, −2   x 2  1 

 x  

1 [1 2]    x 



2



1) The system is completely controllable 2) The system is not completely controllable, but completely observable 3) The system is completely observable 4) The system is not completely observable 88.

Straight line asymptotic Bode magnitude plot  for a certain system is shown in the figure. What will be its transfer function?

4 (1 + s / 4 )

4s

1)

3)

89.

(1 + s / 4 ) (1 + s /10 ) 0.25 (1 + s / 4)(1 + s /10 )

2

2)

(1 + s / 10 )

2

0.25

4)

(1 + s / 4 )(1 + s /10 )

2

For making n-channel enhancement MOSFET  the substrate taken will be of type 1) p 2) n 3) either n or p 4) both n and p

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ME - ELECTRICAL , ELECTRONIC S AND INSTRUMENTATION ENGG. - 2012

98.

In canonic form of IIR system realisation, the number of  1) adders get reduced 2) constant multipliers get reduced 3) unit delay elements get reduced 4) unit delay elements get increased

106. A communication channel disturbed by additive white Gaussian noise has a bandwidth of 4 KHz and SNR of 15. The highest transmission rate that such a channel can support (in K bits/sec) is 1) 16 2) 1.6 3) 3.2 4) 60

99.

Causal sequence f(n), if F(z)=4z –3 (1–z –1)2 is 1) 4(n–2)u(n–2) 2) 4(n–1)u(n–1) 3) 4(n–3)u(n–3) 4) 5(n–4)u(n–4)

107. A full duplex roundtrip delay through a synchronous satellite is approximately 1) 800 m sec 2) 600 m sec 3) 300 m sec 4) 550 m sec

100. The system y(n)= x (n–2)–2 x (n–17) is a 1) DT dynamic system 2) DT static system 3) CT static system 4) Arbitrary system 101. For what value of k does the polynomial s 3+(4+4k)s 2+6s+12 have roots with negative real parts? 1) k–2 3) k=2 4) k=–2

108. When the polarization of the receiving antenna is unknown, to ensure that it receives atleast half the power (except in one particular situation) the transmitted wave should be 1) horizontally polarised 2) vertically polarised 3) circularly polarised 4) elliptically polarised

102. If any coefficients of the characteristic equation of the system are zero, the system is 1) unstable 2) stable 3) marginally stable 4) none of the above

109. Select one sensor characteristics that is most likely to affect the total system gain 1) Offset 2) Response time 3) Accuracy 4) Range

103. BSC frames can be categorised as either  fram es or fram es. 1) transmission, control 2) data, control 3) supervisory, data 4) supervisory, transmission

110. A phase sequence indicator rotates clockwise  for phase sequence RYB if the phase sequence is changed to BRY it will rotate 1) Anticlockwise 2) Clockwise 3) Clockwise or anticlockwise 4) None of the above

.

104. Decryption and encryption of data are the responsibility of layer in the ISO OSI architecture. 1) transport 2) application 3) presentation 4) datalink

111. An aquadag is used in a CRO to collect 1) Primary electron 2) Secondary electron 3) Holes 4) Both primary and secondary electron

105. If the transmission bandwidth is doubled in FM, then the SNR is 1) also doubled 2) improved four fold 3) decreased by one fourth 4) unaffected

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112. A triangular wave shape is obtained 1) By integrating a square wave 2) By differentiating a sine wave 3) By differentiating a square wave 4) By integrating a sine wave

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ME - ELECTRICAL , ELECTRONIC S AND INSTRUMENTATION ENGG. - 2012

113. One of the following can act as an inverse transducer

117. The following flow measurement device requires square root extraction

1) RTD 2) LVDT 3) Capacitive transducer 4) Piezo electric crystal 114. W h i c h

of

the

following

1) 2) 3) 4)

temperature

measurement, devices is based on change in resistance with temperature change? 1) Thermocouple 2) RTD

3) Thermometer

Orifice plate Magnetic flowmeter Cariolis flowmeter Vortex shedding meter

118. W h i c h o n e i s characteristic?

4) Pyrometer

an

1) Accuracy 3) Reproductibility

undesirable

static

2) Sensitivity 4) Drift

115. Hall effect voltage is caused by

1) 2) 3) 4)

Change in capacitance Change in inductance Change in magnetic Change in resistance

119. Mass spectroscopy is used to measure 1) Light spectrum 2) Masses of isotopes

3) Brain singal 4) Transition of electrons

116. The procedure that allows you to change a smart transmitter parameters such as tag engineering units output type (linear/square root) damping etc. is

1) Calibration 3) Configuration

120. Point velocity measurement is done by 1) Bourden tube 2) Pitot tubes

2) A/D conversion 4) Characterisation

3) Piezo electric transducer 4) Diaphragm

ME - ELECTRICAL ELECTRONICS AND INSTRUMENTATION ENGG. 2012 – ANSWERS 76 ....... 1 77 ....... 86 ....... * 87 ....... 9 6 ....... 4 97 ....... 1 0 6 ...... 1 1 0 7 ....... 1 1 6 ...... 3 1 1 7 .......

2 78 ....... 2 79 ........ 1 80 ........ 3 2 88 ....... 3 89 ........ 1 90 ........ 4 3 98 ....... 3 9 9 ........ 2 1 00 ........ 4 1 1 0 8 ....... 2 1 0 9 ........ 3 1 1 0 . ....... 2 1 1 1 8 ....... 3 1 1 9 ........ 2 1 2 0 . ....... 2

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81 ....... 2 82 ....... 91 ....... 2 92 ....... 1 01 ....... 4 1 02 ....... 1 1 1 ....... 2 1 1 2 .......

4

2 83 ....... 4 93 ....... 2 1 03 ....... 1 1 1 3 .......

1 84 ....... 3 85 ........ 1 1 94 ....... 4 95 ........ 4 1 1 04 ....... 3 1 05 ........ 4 4 1 1 4 . ...... 2 1 1 5 ........ 3

ME - ELECTRICAL , ELECTRONIC S AND INSTRUMENTATION ENGG. - 2012