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19th May 2018, 09:18 PM
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Re: DMRC previous year question paper for ECE

Can you provide me previous year question paper for DMRC (Delhi Metro Rail Corporation) JE (Electronics) Post recruitment as I need it for preparation of the exam?
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19th May 2018, 09:21 PM
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Join Date: Aug 2012
Re: DMRC previous year question paper for ECE

The previous year question paper for DMRC (Delhi Metro Rail Corporation) JE (Electronics) Post recruitment is as follows:

Technical Aptitude Questions

1. Which one of the following statements is correct?
Digital modulation techniques are used in satellite communication systems since:
(1) They are easier to handle
(2) Large bandwidth utilization is possible
(3) They have a higher spectral efficiency
(4) They are less prone to interference
Answer : They are less prone to interference

2. How many bits are required to encode 32 level PCM:
(1) 6
(2) 5
(3) 4
(4) 3
Answer : 5

3. The noise is more dominant in which of the following:
(1) PAM
(2) PWM
(3) PPM
(4) FSK
Answer : PAM

4. The phase velocity of wave propagating in a hollow metal wave guide is:
(1) Greater than the velocity of the light in free space
(2) Less than the velocity of the light in free space
(3) Equal to the velocity of the light in free space
(4) Equal to the group velocity
Answer : Greater than the velocity of the light in free space

5. The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is:
(1) 25 ohm
(2) 50 ohm
(3) 75 ohm
(4) 100 ohm
Answer : 50 ohm


6. The line of sight communication requires transmit and receive antenna to face each other. If the transmit antenna is vertically polarized, for the best reception the receive antenna should be:

(1) Horizontally polarized
(2) Vertically polarized
(3) At 45 with respect to the horizontal polarization
(4) At 45 with respect to the vertical polarization



Answer : Horizontally polarized

7. A network contains linear resistance and ideal voltage source. If the value of all the resistors are doubled, then the voltage across each resistor is:

(1) Halved

(2) Doubled

(3) Increased by four times

(4) Not changed



Answer : Not changed

8.Twelve 1 ohm resistances are used as edge to form a cube. The resistance between two diagonally opposite corners of the cube is:

(1) 5/6 ohm

(2) 1 ohm

(3) 6/5 ohm

(4) 3/2 ohm



Answer : 5/6 ohm

9. An eight bit digital data 10101100 is fed to an ADC. The reference voltage is +10V. The analog output voltage will be:

(1) 1.05V

(2) 6.74V

(3) 10.10V

(4) 5.15V



Answer : 6.74V

10. A series RLC circuit has a resonant frequency of 1 KHz and a quality factor Q = 100. If each of the R,L and C is doubled from its original value, the new Q of the circuit is:

(1) 25

(2) 50

(3) 100

(4) 200



Answer : 200

11. The input to a coherent detector is DSB-SC signal plus noise. The noise at the detector output is:

(1) The in-phase component
(2) The quadrature-component
(3) Zero
(4) The envelope



Answer : Zero


12. Gunn diode is a:

(1) Negative resistance device
(2) Positive resistance device
(3) High noise device
(4) Low frequency device



Answer : Negative resistance device

13. The intrinsic carrier concentration of silicon sample at 300 K is 2.5 1016/m3. If after doping, the number of majority carriers is 5 1020 /m3, the minority carrier density is:

(1) 1.25 1012/m 3

(2) 0.125 1012/m3

(3) 2.5 1020/m3

(4) 0.5 104/m3



Answer : 1.25 1012/m 3

14. The unit of ? H is:

(1) Ampere

(2) Ampere/meter

(3) Ampere/meter2

(4) Ampere-meter



Answer : Ampere/meter2

15. A PIN diode is:

(1) A metal semiconductor point-contact diode
(2) A microwave mixer diode
(3) Often used as a microwave detector
(4) Suitable for use as a microwave switch



Answer : Suitable for use as a microwave switch

16. 11001, 1001 and 111001 correspond to the 2s complement representation of which one of the following sets of number?

(1) 25, 9 and 57 respectively
(2) 6, 6 and 6 respectively
(3) 7, 7 and 7 respectively
(4) 25, 9 and 57 respectively



Answer : 7, 7 and 7 respectively

17. To couple a coaxial line to a parallel wire line, it is best to use a:

(1) A slotted line
(2) Balun
(3) Directional coupler
(4) Quarter wave line transformer



Answer : Balun

18. Which of the following is used extensively where lowest power consumption is necessary?

(1) CMOS

(2) NMOS

(3) PMOS

(4) Any of the abov



Answer : CMOS


19. Reflex klystron is a:

(1) Low power generator

(2) High power oscillator

(3) Low gain amplifier

(4) Not an oscillator



Answer : Low power generator

20. If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly:

(1) 8.24 KW

(2) 9.26 KW

(3) 8.47 KW

(4) 9.6 KW



Answer : 8.47 KW


21. The current through 8 ohms branch is:


(1) 1A

(2) 0.5A

(3) 1.5A

(4) None of these



Answer : 0.5A



22. JFET in properly biased condition acts as a:

(1) Current controlled current source
(2) Voltage controlled voltage source
(3) Voltage controlled current source
(4) Impedance controlled current source



Answer : Voltage controlled current source

23. The circuit shown in figure is best described as a:



(1) Bridge rectifier

(2) Ring modulator

(3) Frequency discriminatory

(4) Voltage doubler



Answer : Voltage doubler


24. Which amplifier will be preferred for highest gain?

(1) Darlington pair
(2) Cascade amplifier
(3) Cascode amplifier
(4) Depends on the circuitry



Answer : Cascode amplifier
Attached Files
File Type: doc Question Paper DMRC JE (Electronics) Post.doc (91.0 KB, 55 views)


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