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(Paper) RRB ALP Paper Stage-2 : Exam Paper & Answer Key Held on 21-Jan-2019 Shift-2 (Electronic Mechanic)

(Paper) RRB ALP Paper Stage-2 : Exam Paper & Answer Key Held on 21-Jan-2019 Shift-2
(Electronic Mechanic)

Q1. Which one of the gates mentioned below works as ‘parity checker’?

a. OR 
b. Ex-OR
c. AND

Q2. A PC consuming 100 Watts is to be operated on UPS. The UPS uses a 12 volts, 100 AH battery. Assuming unity PF,what is the backup time of this unit?

a. 8 Hours
b. 16 Hours 
c. 24 Hours 
d. 12 Hours 

Q3. What is the typical frequency and type of modulation used in an IR Remote control for TV?

a. 38 KHz, PCM
b. 98.1 MHz, AM
c. 98 KHZ, PM
d. 108.1 KHz, FM

Q4. Which one of the following can be used as a photo detector in Fiber Optic communication?

a. Tunnel diode
b. LASER diode 
c. PIN Diode 
d. LED

Q5. Which of the following is NOT a type of trigger in Digital Storage Oscilloscope?

a. Edge 
b. Video 
c. Level 
d. Pulse width 

Q6. The principle of magnetic attraction and repulsion works in:

a. MI Instruments 
b. Digital multimeter
c. CRO
d. PMMC Instruments 

Q7. The synchronous speed of an induction motor is 1,000 RPM . Find the percentage slip if its actual rotation speed is 980 RPM?

a. 8
b. 20
c. 2
d. 4

Q8. In which frequency band does a 2GHz signal lie?

a. HF
b. UHF
c. EHF
d. VHF

Q9. Proximity sensors are used to ________.

a. Detect non-magnetic but conductive materials 
b. Measure distance 
c. Measure strain 
d. Measure temperature

Q10. An Op Amp has a Gain Bandwidth Product of 1 MHz. At what frequency will the gain of this Op Amp be equal to unity? Identify from the options given below.

a. 100 KHz
b. 10 KHz
c. 1,000 KHz
d. 10 MHz

Q11. Identify the main reason why an Ammeter should have very low internal resistance.

a. It should decrease the circuit resistance.
b. It should not burn.
c. It should provide damping.
d. It should not affect the circuit resistance.

Q12. When the LED lights need a range of voltages to operate, which of the following drivers is best suited for the job?

a. Constant impedance 
b. Constant frequency 
c. Constant voltage 
d. Constant current 

Q13. Which of the following is NOT a type of optocoupler?

a. Photo Resistor type 
b. Photo TRIAC type
c. Photo SCR type 
d. Photo Transistor type

Q14. For currents as high as 2,000 Amps, which of the  following types of fuses is the best choice?

a. HRC Fuse 
b. LRC fuse 
c. Glass Cartridge Fuse 
d. Nichrome Wire Fuse 

Q15. TRIAC is similar to _________.

a. Two diodes connected in parallel. 
b. Two SCR connected in parallel.
c. Two SCR connected in series back to back.
d. Two diodes connected in series back to back.

Q16. The number of input lines in a common BCD to seven segment decoder is________.

a. 4
b. 16
c. 8
d. 2

Q17. 180 coulombs of charge passes in a given time “t” through a wire of 1 ohm when connected to a 3 V DC supply. Identify the value of “t” from the options given.

a. 0.5 Minutes 
b. 2 Minutes 
c. 1.5 Minutes 
d. 1 Minutes 

Q18. When a star Delta Starter is used with 3-phase squirrel cage motors, in which sequences is the connection made?

a. First Delta, then star and again Delta modes 
b. First Delta, then Star Modes
c. First Star, then Delta modes 
d. First star, then Delta and again star mode

Q19. In the voltage amplifier ________.

a. Output voltage is larger than the input voltage.
b. Output voltage is lower than the input voltage.
c. Output voltage is zero.
d. Output voltage is equal to the input voltage.

Q20.  which type of proximity sensor is not suitable for detecting ‘Glass Bottles ’?

a. Inductive type 
b. Capacitive type
c. Ultrasonic type 
d. Photoelectric type

Q21. The number of Flip Flops required for constructing a MOD 12 counter is ______.

a. 5
b. 4
c. 3
d. 6

Q22. Ten cells, each of 2 volts emf and 1 ohm internal resistance are connected  across this combination of cells?

a. 1 A
b. 100 mA
c. 1 mA
d. 10 mA

Q23. Online UPS requires 

a. Only rectifier 
b. Only battery 
c. Both rectifier and inverter 
d. Only inverter

Q24. Identify the frequency of the crystal used for outgoing calls in mobile phones.

a. 26 MHz
b. 5.5 MHz
c. 108 MHz
d. 99 MHz

Q25. By using the AC coupling mode in a CRO________. 

a. Only AC signal can be viewed on the display.
b. Both AC and DC signals can be viewed on the display.
c. Any signal cannot be viewed on the display.
d. Only DC signal can be viewed on the display.

Q26. In the full-wave Rectifier, relation between peak value and rms value is:

a. Vp=√1.2Vrms
b. Vp=√2Vrms
c. Vp=√4Vrms
d. Vp=√3Vrms

Q27. The emitter of which of the below mentioned transistors has electrons as the majority carriers?

a. PNP
b. NPN
d. N Channel 

Q28. What are the logic levels in case of TTl logic using +5V as Vcc?

a. -0.3 to 0.3 V for logic 0 and 2.8 V to Vcc for logic 1
b. -0.1 to 0.6 V for logic 0 and 1.7 V to Vcc for logic 1
c. 0 to 0.3 V for logic 0 and 0 V to Vcc for logic 1
d. 0 to 0.8 V for logic 0 and 2 V to Vcc for logic 1

Q29. which of the following rectifiers needs a ‘center tapped transformer’?

a. Two -phase Full Wave Rectifier 
b. Full wave Bridge Rectifier 
c. Half Wave Rectifier 
d. Full Wave two-diode Rectifier

Q30. _____is used to describe the information about the hue and saturation of a colour.

a. Phosphorescence 
b. Sharpness 
c. Chrominance 
d. Luminance 

Q31. If two equal resistances are connected in parallel configuration then the resultant resistance will be:

a. Double of the resistance value 
b. Half of the resistance value 
c. Multiplication of both the resistance
d. Zero

Q32. Identify the WRONG statement from the options given below.

a. LEDs are used for backlighting the LCD screen of LED TV.
b. CFLs are used for backlighting the LCD screen of LED TV.
c. Both LCD and LED TVs use an LCD screen for display.
d. In LED TV, the LEDs can be placed on the edges too.

Q33. Which of the following modulation techniques uses two carriers?

a. FSK
b. TDM
c. ASK
d. QAM

Q34. Which of the following is used with LED lamps to focus its entire lighting output in one direction?

a. Parabolized Aluminum Reflector 
b. Aluminum Channels 
c. Parabolized Aluminum Reflector 
d. Aluminum Panels 

Q35. Power loss in a transformer is known as the ______.

a. Difference of current between the secondary and primary coils.
b. Addition of power in the secondary and primary coils.
c. Difference of voltage between the secondary and primary coils.
d. Difference of power between the primary and the secondary coils . 

Q36. Which one of the following circuits allows control of the SMPS output?

a. LC filter circuit 
b. LCL filter circuit 
c. EMI filter circuit 
d. PWM circuit 

Q37. Why is the transformer of an SMPS smaller in size when compared to a transformer in a Linear Power Supply of similar rating ?

a. Because of HF operation 
b. Because of higher efficiency 
c. Because of lower PF 
d. Because of smaller currents 

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Q38. In computers, some areas in the memory is reserved for high speed operations and storing frequently used instructions. What is the name of this type of memory?

a. Cache 
c. Flash 
d. Northbridge 

Q39. Which of the following connectors is used for telephone / modem interface?

a. RJ32
b. RJ11
c. RJ45
d. RJ67

Q40. What is the length of the antenna needed to a signal of 500 KHz frequency?

a. 1 Km
b. 100 M
c. 6 Km
d. 600 m

Q41.What is the ratio of RMS to the average Value is known as?

a. Maximum value 
b. Peak factor 
c. Form factor
d. Effective factor 

Q42. Identify the main feature of power amplifiers from the options given below:

a. They cannot be operated without transformers 
b. They have voltage amplifiers in the preceding stage.
c. Their output voltage is high 
d. Their output impedance is high  

Q43. Astable multivibrator operating at 100 Hz has a discharge time of 2ms. Find the duty cycle of the circuit .

a. 10%
b. 50%
c. 20%
d. 30%

Q44. Which of the following statements is true for Bi Colour LEDs?

a. A special dopant is used for producing two colours in one LEDs 
b. Two different colour LEDs are connected in series in the reverse direction
c. Two different colour LEDs are connected in inverse parallel 
d. Two different colour LEDs are connected in series in the same direction 

Q45. In mobile phones, when a user puts the phone to his/ her the screen goes off. Which is the sensor used for this?

a. Proximity sensor 
b. Vibration sensor 
c. Temperature sensor 
d. Motion sensor 

Q46. Which frequency range is used for TV? 

a. UHF
b. VLF
c. ULF
d. HF

Q47. Identify the port shown in the image below. 

a. HDMi 
b. Fire wire 
c. DVI 

Q48. Which system allows the entire bandwidth to be available to each user at the same time?

a. GSM 
b. CSMA 

Q49. Three capacitors each of 1u F, 2u F and 3u F are connected in series. Identify the statement which combination.

a. The charge stored by each capacitor is the same.
b. Current flowing through each capacitor is different.
c. The voltage across each capacitor is same.
d. Each capacitor stores a different charge.

Q50. What is the purpose of using bypass diodes in the series connected solar panels?

a. Increasing the current through shaded cells 
b. Protection of shaded cells
c. To redirect light for shaded cells 
d. To increase the resistance of shaded cells

Q51. An LCR meter is used to measure ______.

a. Voltage
b. Current 
c. Inductance 
d. Power
Answer:- C

Q52. The hexadecimal equivalent of the decimal number 4096 is______.

a. 1F0
b. F100
c. F00
d. 1,000

Q53. The primary voltage of a transformer is 200 volts and the secondary voltage is 50 volts. If the number of turns in the secondary winding is 100, the number of turns is the primary is ______.

a. 200
b. 100
c. 400
d. 800

Q54. Refractive Index of the medium is the ratio of_____.

a. Velocity of light in the water to the velocity of light in the vacuum
b. Velocity of light in water to the velocity of light in air 
c. Velocity of light in the vacuum to the velocity of light in the medium 
d. Velocity of light in the vacuum to the velocity of light in the vacuum

Q55. The Octal equivalent of the hexadecimal number 100 is ______.

a. 400
b. 300
c. 200
d. 600

Q56. Which is the device commonly used in domestic fan speed control circuits?

a. SCR
d. SCS

Q57. Optical Time Domain Reflectometer is used to measure:

a. Loss in optical communication 
b. Eye pattern 
c. Dispersion in optical fibre 
d. Wavelength 

Q58. What is the size of internal data memory in a 8051 microcontroller?

a. 128 bytes
b. 256 bytes
c. 1,024 bytes
d. 2,048 bytes
Answer:- A

Q59. The IC 74LS138 is a _______.

a. 8 bit adder
b. 8 line multiplexer
c. 8 line demultiplexer
d. 8 bit subtractor

Q60. what is the peak to peak of a sine waveform whose average value is 12.74 volts?

a. 40 V
b. 20 V
c. 10 V
d. 30 V

Q61. Which one of the following can be used to test the characteristics of an OFC?

a. OFCM(Optical Fiber Communication Module)
b. OTDR(Optical Time Domain Reflectometer)  
c. DTDR(Digital Time Domain Reflectometer)
d. OTMM(Optical Transceiver Monitoring Module)

Q62. How many dual purpose ports are there in the 8051 microcontroller ?

a. 1
b. 4
c. 3
d. 2

Q63. FET is a _______.

a. Current and voltage controlled device 
b. Voltage controlled device 
c. Current controlled device 
d. Power controlled device 

Q64. The deflecting torque in a moving-Iron meter is ______.

a. Inversely proportional to square of the current 
b. Proportional to the square of the voltage 
c. Inversely proportional to the current 
d. Proportional to the square of the current 

Q65. If a JK FF toggles more than once during one clock cycle it is called_____.

a. Pinging
b. Bouncing 
c. Spiking 
d. Racing 

Q66. Which of the following is NOT a function of the LED Driver?

a. Preventing damage against EMI
b. Preventing damage to LEDs by Regulating the forward voltage (Vf)
c. Avoiding thermal runaway 
d. Delivering a constant current to the LED

Q67. The carrier of an AM signal has a power of 1,000 Watts. If the percentage of modulation is 80, what is the power in the upper sideband?

a. 800 Watts
b. 640 Watts
c. 320 Watts
d. 160 Watts

Q68. Which among the following is NOT the function of an Operating system?

a. File Management 
b. Device Management 
c. Memory Management 
d. Data Analysis  

Q69. Push-Pull amplifiers are ______.

a. Class B amplifiers 
b. Class C amplifiers 
c. Class AB amplifiers 
d. Class A amplifiers 

Q70. The present state of the output of an SR flip flop is HIGH. If both its inputs become LOW, what would be the new state of the output?

a. LOW
c. Unpredictable 
d. Toggling 

Q71. Which one of the following instructions is used to “Move Immediate Data to Register” in 8051?

a. MOV A, Rn
b. MOVRn, direct 
c. MOV Rn
d. MOV direct, Rn

Q72. In an Op Amp integrator circuit, what is done to limit the gain at ‘Low Frequencies’?

a. A large capacitor is connected across the output.
b. A large resistor is connected in series with the output 
c. A large resistor is connected across the feedback capacitor 
d. A small capacitor is connected in series with the input 

Q73. In which type of network topology computers are connected to a centralized Hub/switch 

a. Bus Topology 
b. Ring Topology
c. Mesh Topology
d. Star Topology

Q74. which one of the following sensors producers a voltage output upon sensing  temperature?

a. Thermostat
b. Thermocouple 
c. Strain Gauge 
d. RTD

Q75. Based on which principle does a MC meter work?

a. Faraday’s Voltage law
b. Ohm’s law
c. Maxwell’s law
d. Faraday’s Current law

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