ONGC Technical-Electronics |   4041

ONGC Technical-Electronics

                                     ONGC Placement Paper For Electronics

1. Two coils in differential connection have self-inductance of 2 mH and 4 mH and a mutual inductance of 0.15 mH. The equivalent inductance of the combination is
A . 5 .7 mH 
B. 5 .85 mH 
C. 6 mH 
D. 6.1 5 mH. 

2. Optocouplers combine
A . SITs and BJTs 
B. IGBTs and MOSFETS 
C. Power transformers and silicon transistor 
D. Infrared light-emitting diode and a silicon phototransistor 

3. The difference between the indicated value and the true value of a quantity is known as
A . Gross error
B. Absolute error
C. Dynamic error
D. Relative error

4. The principles of homogeneity and super -position are applied to :
A . linear time variant systems
B. non-linear time variant systems
C. linear time invariant systems
D. non-linear time invariant systems.

5. In a 80 85 microprocessor system with memory mapped I / 0 ,
A. I/0 devices have 8-bit addresses
B. I/0 devices are accessed using IN and OUT instructions 
C. there can be a maximum of 2 5 6 input devices and 2 5 6 output devices. 
D. arithmetic and logic operations can be directly performed with the I / 0 data. 

6. In any transmitting antenna system, efficiency primarily depends upon
A . ohmic losses of various conductors
B. radiation resistance
C. ground conductivity
D. atmospheric conditions.

7. An instruction used to set the carry Flag in a computer can be classified as
A . data transfer
B. arithmetic
C. logical
D. program control

8. The binary representation of 5 .3 7 5 is
A . 1 1 1 .1 0 1 1
B. 1 0 1 .1 1 0 1
C. 1 0 1 .0 1 1
D. 1 1 1 .0 0 1

9. Dislocations in materials are
A . point defect
B. line defect
C. planer defect
D. surface defects.

10. In TV system, vertical pulses are separated out from horizontal pulses by the use of
A . integrator
B. differentiator
C. sweep credit
D. sync separator .

11. Frequency in the UHF range propagate by means of
A . Ground waves
B. Sky waves 
C. Surface waves 
D. Space waves. 

12. 200 MHz may be classified as
A . VHF 
B. SHF 
C. UHF 
D. EHF 

13. A communication satellite is a repeater between 
A . a transmitting station and a receiving station 
B. a transmitting station and many receiving stations 
C. many transmitting stations and many receiving stations 
D. none of the above 

14. The efficiency of a chopper can be expected in the range
A . 5 0 to 5 5 percent
B. 6 5 to 7 2 percent
C. 82 to 87 percent
D. 92 to 99 percent

15. Which one out of the following instruments should be used to measure 6 0 0 kV a.c . voltages?
A . Hot wire instrument
B. Electrostatic voltmeter 
C. Moving coil voltmeter 
D. Moving iron voltmeter . 

16. With reference to figure , value of VCE is
1.0 V
2.5 V
3.-5 V
4. none of the above

17. The smallest change in sound intensity that can be detected
A . 1 dB
B. 3 dB 
C. 10 dB 
D. 20 dB. 

18. In a generic microprocessor , instruction cycle time is 
A . shorter than machine cycle time 
B. larger than machine cycle time 
C. exactly double the machine cycle time 
D. exactly the same as the machine cycle time 

19. Resistivity of electrical conductors is most affected by
A . temperature 
B. pressure 
C. composition 
D. all of the above . 

20. In CCIR B-system of TV , blanking pulse is placed during
A . equalizing pulse
B. retrace interval between each line
C. retrace period of vertical line
D. none of the above .

21. The polarization required in ground wave propagation is
A . Horizontal (linear )
B. vertical (linear ) 
C. Circular 
D. Elliptical 

22.Multicavity Klystron
A . is not a microwave device 
B. is not a good low level amplifier because of noise 
C. is not suitable to pulse operation 
D. has a high repeller voltage to insure small transit time 

23.Transponder comprises of
A . Transmitter 
B. Receiver 
C. Antenna 
D. a, b , c combined 

24.Which of the following regulator provides output voltage polarity reversal without a transformer
A . Buck regulator
B. Boost regulator 
C. Buck-boost regulator 
D. Cuk regulator 

25. The deflection of hot wire instrument depends on 
A . RMS value of alternating current 
B. voltage 
C. average value of a.c . current 
D. instantaneous value of a.c . current. 

26.Dual slope integration type Analog-to -Digital converters provide
A . higher speeds compared to all other types of A / D converters 
B. very good accuracy without putting extreme requirements on component stability 
C. poor rejection of power supply hums 
D. better resolution compared to all other types of A / D converters for the same number of bits. 

27. The frequency modulated (FM) radio frequency range is nearly
A . 2 5 0 - 3 0 0 MHz
B. 1 5 0 - 2 0 0 MHz
C. 9 0 - 1 0 5 MHz
D. 3 0 - 7 0 MHz

28. A 3 2 bit microprocessor has the word length equal to
A . 2 bytes
B. 1 byte 
C. 4 bytes 
D. 8 bytes 

29. Line imperfection in a crystal is called
A . Schottky defect
B. Frenkel defect 
C. edge dislocation 
D. Miller defect. 

30. The function of diplexer bridge in a TV transmitter is 
A . to prevent the loading of several transmitters by video transmitter 
B. to increase the bandwidth 
C. to increase the power output 
D. to increase the efficiency of transmission. 

31. Sometimes microwave signals follow the earth’s curvature . This due to
A . Ionospheric reflection
B. Faraday rotation 
C. Ducting 
D. Ionospheric scatter . 

32. The modes in a reflex Klystron 
A . give the same frequency but different transit time 
B. result from excessive transit time across the resonator gap 
C. are caused by spurious frequency modulation 
D. are just for theoretical considerations. 

33. The capacity of a channel is
A . number of digits used in coding 
B. volume of information it can take 
C. maximum rate of information transmission 
D. bandwidth required for information

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