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BSNL Placement Paper (Set-4)

BSNL Sample Paper Pattern (Set-4)

1.For a transmission line, the propogation constant, for a TEM wave travelling in it is given by (Where the symbols have the usual meanings ) - 
a)  [ (R+jwL) (G+jwc)] 
b) [ R+jwL) (G+jwc)] ? 
c)? [ (R-jwL) (G + jwc) ] ? 
d) [(R-jwL) ( G+jw2c)]1/3 ?

2.The advantages of wave guides over co-axial lines would include which of the following features- 
1. Easier to use     2. lower power losses 
3. Higher operating frequencies possible 
a)  1 and 2 
b) 1 and 3 
c)  2 and 3 
d) 1,2 and 3 ?

3.When a 75 ohm transmission line is to be terminated in two resistive loads R1 and R2 such that the standing pattern in the two cases have the same SWR , then the values of R1 and R2  (in ohms) should be -
a)  250 and 200 respectively 
b) 225 and 25 respectively 
c)? 100 and 150 respectively 
d) 50 and 125 respectively?

 5.The degenerate modes in a wave guide are characterized by - 
a)  Same cut off frequencies but different field distribution 
b) Same cut off frequencies and same field distributions 
c)? Different cut off frequencies but same field distributions 
d)  Different cut off frequencies and different field distributions?

6.A TEM wave impinges obliquely on a dielectric-dielectric boundary with Er1=2 and Er2=1, the angle of incidence for total reflection is - 
a)? 30 0 
b)? 60 0 
c)  45 0 
d) 90  0 ?

7.The radiation  pattern  of Hertzian dipole in the plane perpendicular to the dipole is a - 
a)  Null 
b) Circle 
c)  Figure of eight 
d) None of the above   ? ?

8.. Permeance is the - 
a) square of reluctance 
b) reluctance 
c) reciprocal of the reluctance 
d) cube of the reluctance. ?

9.One of the following which is an active transducer is - 
a) Photoelectric 
b) Photovoltaic 
c) Photo-conductive 
d) Photo emission ?

 10.The wein bridge  uses only - 
a) Inductors 
b) Capacitors 
c) Resistors 
d) Capacitors and Resistors. ?

11.The greater the value of Q - 
a) higher will be the bandwidth of the resonant circuit. 
b) smaller will be the bandwidth of the resonant circuit. 
c) nothing can be said) 
d) none. ?

 12.The most serious source of error in a) c) bridge measurement is - 
a) eddy currents 
b) leakage currents 
c) residual imperfectness 
d) stray fields. ?

13.Moving iron instruments - 
a) have a linear scale 
b) do not have a linear scale 
c) both a and b) 
d) none. ?

14.If accuracy is the main consideration, which one of the following voltmeters should one select - 
a) 100 v ; 2 mA 
b) 100 v ; 100 ohm/volt 
c) 100 v ; 1mA 
d) 10,000 v ; 10 mA ?

15.In dc tacho generators used for measurement of speed of a shaft, frequent calibration has to be done because - 
a) the contacts wear off 
b) the strength of permanent magnet decreases with age 
c) the armature current produces heating effect 
d) there is back emf. ?

16.Ideal transformer cannot be described by - 
a) h parameters 
b) ABCD parameters 
c) G parameters 
d) parameters ?

17.Consider the following statements - 
A3- phase balanced supply system is connected to a 3 phase unbalanced load) Power supplied to this load can be measured using 
1. Two wattmeters 
2. One wattmeter 
3. Three wattmeters 

18.Which of these statements is/are correct? 
a) 1 and 2 
b) 1 and 3 
c) 2 and 3 
d) 3 alone?

19.The function of the reference electrode in a pH meter is to - 
a) Produce a constant voltage 
b) Provide temperature compensation 
c) Provide a constant current 
d) Measure average pH value?

20.Match the column A (Devices) with column B (Characteristics) and select the correct answer by using the codes given below the column -
Column A                                              Column B 
A) BJT                                                   1. Voltage controlled negative resistance 
B) MOSFET                                          2. High current gain 
C) Tunnel diode                                   3. Voltage regulation 
D) Zener diode                                     4. High input impedance 
Codes : 
        A             B             C             D 
a)             1              4              2              3 
b)             2              4              1              3 
c)             2              3              1              4 
d)             1              3              2              4 ?

21.A thyristor during forward blocking state is associated with.- 
a) large current , low voltage. 


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