Nepal Airlines (Avionics)-7th Level



२०७४/०४/१४ 
Full Marks: 100
Multiple Choice Question

     Q1. The following unit is used to supervise each instruction in the CPU
A) Control logic unit 
B) Accumulator 
C) ALU 
D) Control register
Ans:

    Q2. When a capacitor was connected to the terminal of ohmmeter, the pointer                   indicated a low resistance initially and then slowly came to infinity position.                 This shows that capacitor is
(a) Short-circuited (b) all right (c) faulty (d) None of the
Ans: b

     Q3. What device is used to measure the very high insulation resistance of electric              cables?
A) High resistance voltmeter 
B) Moving iron vane meter 
C) Megger 
D) Multimeter
Ans: C

     Q4. In a balanced Wheatstone bridge, across the center of the bridge there is
           a) No current flow 
           b) No voltage is present at either end 
           c) Current always flows in one direction only 
           d) Current and voltage are at a new maximum
     Ans: a

    Q5. When an AC current of 5A and dc current of 5A flow simultaneously through a             circuit then which of the following statement is true?
     a) An ac ammeter will read less than 10A but more than 5A
     b) An ac ammeter will read only 5A

     c) A dc ammeter will read 10A

     d) A dc ammeter will read zero

     Ans: - An ac ammeter will read less than 10A but more than 5A

    Q6. Which of the following is correct in reference to electrical resistance?
    a) Two electrical devices will have the same combined resistance if they are connected             in series as they will have if connected in parallel
    b) If one of three bulbs in a parallel lightening circuit is remove, the total resistance of the          circuit will become greater
    c) An electrical device that has a high resistance will use more power than one with a low          resistance with the same applied voltage
     d) A 50 Ohm resister in a 12 volt circuit will use less than a 10 Ohm resister in a 24 volt             circuit
     Ans:

     Q7. The voltage output of an alternator may be regulated by controlling the

     a. speed of the alternator.
     b. voltage output of the dc exciter.
     c. resistance in the rotor windings.

     Ans: b
~ The voltage output of an AC alternator is determined by the amount of current flowing in its exciter field. The alternator output voltage may be controlled by varying the output voltage of the DC exciter. 

     Q8. An SCR combines the features of …………..
    a.    A rectifier and resistance
    b.    A rectifier and transistor
    c.    A rectifier and capacitor
    d.    None of the above
     Ans: d

     Q9. The first law of thermodynamics is the law of
Ans:

     Q10. When a drawing is amended which does not affect interchangeability, the

Ans: The usual practice when a drawing is changed is to re-issue it with a new revision number.

     Q11. Management is defined as

     Q12. Execution of a quality plan should be the responsibility of

Ans: All quality plans are controlled by management and the quality of the project is the main responsibility of project managers.

Q13. Which of the following is NOT an objective of MIS?
A) Facilitate the decisions-making process
B) Provide requisite information at each level of management
C) Support decision-making
D) Recruit people for system
Answers: D)
Q14. the following can be considered to measure quality
a.        Customer satisfaction
b.       Defects
c.        Rework
       d.       All of the above
e.        None of the above
Ans: d
Q15. which of the following statement is false in the context of quality assurance and quality control
Quality control is focused on fulfilling quality requirements, whereas quality assurance is focused on providing confidence that quality requirements are fulfilled.

 Q16. Indicate which of the following pulse modulation systems is analog
A. PCM
B. PWM
C. Differential PCM
D. Delta
Q17. fragmenting in the uhf range normally propagate by means of
a) Ground waves
(b) sky waves
(c) surface waves
(d) space waves.
Answers. (d)
Q18. in a class c amplifier with sinusoidal input signal, the output current flows for
Q19. linear diode detector utilizes
 A. 
linear portion of static characteristics of diode
 B. 
linear portion of dynamic characteristic of diode
 C. 
square law portion of dynamic characteristics of diode
 D. 
rectification property of diode
Answer: D
Q20. for a silicon transistor to conduct
transistor will not conduct (that is, no current will flow through from the collector to the emitter) unless there is a also potential difference between the emitter and the base of at least 0.6 V
Q21. Bleeder resistor in power supplies is used to place

Q22. Radio Horizon: The radio horizon for space waves is about four-thirds as far as the optical horizon. This beneficial effect is caused by the varying density of the atmosphere, and because of diffraction around the curvature of the earth. It is given with good approximation, by the empirical formula dt=4 √ht where dt= distance (in km) from the transmitting antenna, ht = height (in m) of transmitting antenna above the ground. The same formula applies to the receiving antenna.


Q23. Waveguide acts as a high pass filter in that most of the energy above a certain frequency (the cutoff frequency) will pass through the waveguide, whereas most of the energy that is below the cutoff frequency will be attenuated by the waveguide.

Q24. The voltage standing wave has the node and the current standing wave the anti node with
There is a voltage standing wave, as well as current standing wave. Both have exactly the same shape, only that they are out of phase with each other to λ/4, ie at one's voltage antinode, corresponds a current node of the other and vice versa.
Q25. VHF communication transmissions are

Q26. The directional characteristics of combined vertical dipole and loop antenna arrangement is a
Some advantages of optical fiber cables are

Q27. Directive gain is
Antenna gain is usually defined as the ratio of the power produced by the antenna from a far-field source on the antenna's beam axis to the power produced by a hypothetical lossless isotropic antenna, which is equally sensitive to signals from all directions.

Q28. When a wave travelling in air enters into a wave guide
(A)  The phase velocity will increase.
(B)   The group velocity will increase.
(C)   The phase velocity will decrease.
(D)  None

Q29. The term critical frequency denotes
A.
the lowest frequency that is reflected by the ionosphere
B.
the highest frequency that is reflected by the ionosphere at vertical distance
C.
the lowest frequency by which communication is possible between two given points
D.
none of the above
Answer: Option B

Q30. The three forces in a meter are

Q31. A galvanometer can be used for measuring current and voltage of a circuit by

Q32. When used in a power supply the function of a zener diode is to maintain constant

Q33. In modern electronic multimeter, a FET or MOSFET is preferred over BJT because

Its input resistance is high  
Its input resistance is high and does not change with range switch
Its input resistance is low  
It is cheaper

Q34. The sensitivity of a voltmeter is commonly expressed in ohms per volt, which is the total resistance  the sensitivity of a voltmeter is commonly expressed in ohms per volt, which is the total resistance of the meter (r+rm) divided by the full-scale reading.

Q35. To measure a resistance of about 8 ohms, we would use

Q36. A synchro is a electromagnetic transducer used to convert the angular shaft position into electric signals.

Q37. Calibrated airspeed (CAS) corrects the indicated airspeed for errors primarily resulting from the position of the static source and, to a much lesser degree, from pitot tube locations. The major errors are mainly due to differences in airflow over the static port at varying angles of attack. The errors usually are greatest in the low and high-speed ranges and smallest in normal op

Q38. A thyristor (silicon controlled rectifier-scr)

Q39. The VHF communication band with 8.33 khz spacing produces

Q40. Which system on aircraft uses to communicate with ground control?
A larger answer is that ground control and aircraft communications were under major development for decades before satellite communications were available. The system we use today is heavily based on line-of-sight VHF communication radio over most populated areas.

Q41. After an automatic direction finding antenna has been installed, the
~ When an automatic direction finder is installed on a particular type of aircraft for the first time, it is important that the loop antenna be checked for quadrantal error. Quadrantal error is the error caused by the metal in the aircraft structure distorting the electromagnetic field of the received signal. Quadrantal error causes azimuth inaccuracies, which are greatest between the four cardinal points with respect to the center line of the aircraft. 
a. antenna must be grounded.
*b. loop must be calibrated.
c. transceiver must be compensated.

Q42. A DME antenna should be located in a position on the aircraft that will
~ To prevent an interruption in DME operation, the antenna must be located in a position that will not be blanked by the wing when the aircraft is banked.

*a. not be blanked by the wing when the aircraft is banked.
b. permit interruptions in DME operation.
c. eliminate the possibility of the DME locking on a station.

Q43. Which one of the following is not correct?
(a) Bus is a group of wires
(b) Bootstrap is a technique or device for loading first instruction 
(c) An instruction is a set of bits that defines a computer operation
(d) An interrupt signal is required at the start of every programme

Q44. The working voltage of a capacitor is
The Working Voltage is another important capacitor characteristic that defines the maximum continuous voltage either DC or AC that can be applied to the capacitor without failure during its working life. 

Q45. To find the resonant frequency of a circuit the following formula is used
Description: Resonant Frequency Formula
Q46. Which symbol represents a variable resistor
Description: variable resistor symbol
Q47. The boiling point of a given liquid varies
A-    directly with pressure.
B-     inversely with pressure.
C-     directly with density.

Q48. An isothermal process is one in which
An isothermal process is one in which the temperature remains constant.

Q49. An isometric projection is
Isometric projectionIsometric (meaning “equal measure”) is a type of parallel (axonometric) projection, where the X and Z axes are inclined to the horizontal plane at the angle of 30. The angle between axonometric axes equals 120. 30/120/30 is also referred ti as true isometric grid.


Q50. Which of the following is not considered a method of heat transfer


2076/02/07

Aircraft Maintenance /Avionics Group/ 7th Level/ Senior Technical Officer

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