DRDO EEE Previous Papers

Hi I would like to have sample questions for the previous years question paper for Electrical Engineering for the Defence Research and Development Organisation?

[Kiran Chandar]

The sample questions for previous years question paper for Electrical Engineering for the Defence Research and Development Organisation is as follows:

Q.1:- Two materials have resistance temperature coefficients of 0.004 and 0.0002 respectively at a given temperature. In what ratio should the wires made of these materials be connected in series so as to have an overall temperature coefficient of 0.002?
(a) 1:2 (b) 2:3 (c) 9:10 (d) 15:16

Q.2:- Consider the two fields,
E = 120 𝜋 cos (10⁶𝜋 t- x) V / m
And
H = A cos (10⁶𝜋 t- x) / m.
The values of A and β which will satisfy the Maxwell’s equation in a linear isotropic, homogeneous, loss-less-medium with = 8 and
= 2 will be
A (in A / m) β (in rad / m)
1 0.0105
1 0.042
2 0.0105
2 0.042

Q.3:- A chopper operating at a fixed frequency is feeding an R-L load. As they duty ratio of the choppe is increased from 25% to 75%, the ripple in the load current.
Remains constant.
Decreases, reaches a minimum at 50% duty ratio and then increases.
Increases, reaches a maximum at 50% duty ratio and then decreases.
Keeps on increasing as the duty ratio is increased.

Q.4:- A sinusoidal waveform, when observed on an oscilloscope, has a peak to peak amplitude of 6cm. If the vertical sensitivity setting is 5 V / cm, the rms value of the voltage will be
(a) 10.6 V (b) 11.1 V (c) 12.6 V (d) 15 V

Q.5:- Which of the following is an example of an open-loop system?
Household refrigerator.
Respiratory system of an animal.
Stabilization of air pressure entering into a mask.
Execution of a program by a computer.

Q.6:- A binary tree T has n leaf nodes. The number of nodes of degree 2 in T is
(a) n (b) n – 1
(c) n (d)

Q.7:- An n-channel silicon (= 1.1 eV) MOSFET was fabricated using n⁺ poly silicon gate and the threshold voltage was found to be 1 V. Now, if the gate is changed to p⁺ poly-silicon, other things remaining the same, the new threshold voltage should be
(a) –0.1 V (b) 0 V (c) 1.0 V (d) 2.1 V

Q.8:- Scintillation is
Variation of physical dimensions under the influence of magnetic field.
Deionization of gases under low pressures.
Production of flashes of light by some substances when struck by alpha, beta of gamma rays.
Change in dielectric constant of substances with change in humidity.

Q.9:- Which of the following statements is true?
ROM is Read /Write memory.
PC points to the last instruction that was executed.
Stack works on the principle of LIFO.
All instructions affect the flags.

Q.10:- In which range the cost of a synchronous motor is likely to be comparable to the cost of induction motor?
Low H.P., high speed.
High H.P., low speed.
High H.P., high speed.
Low H.P., low speed.

Q.11:- which one of the theories given below is related to the theory of the thermocouple?
(a) Piezoelectric effect (b) Skin effect (c) See back effect (d) Faraday’s Law

Q.12:- For the purpose of analysis exact equivalent circuit of a transformer is usually replaced by an approximate equivalent circuit. In doing so errors introduced due to winding copper loss and core loss are of differential nature. Due to this the analysis by approximate equivalent circuit gives fairly satisfactory results. Under the circumstance, which one of the following is correct in respect of losses referred to approx. Equivalent circuit?
This accounts for somewhat greater primary winding copper loss and more cores less core loss.
This accounts for somewhat lesser primary winding copper loss and more core loss.
This accounts for somewhat greater secondary winding copper loss and less core loss
This accounts for somewhat lesser secondary winding copper loss and more core loss.

Q.13:- Consider the following statements: In a 3-phase induction motor connected to a 3-phase supply; if one of the lines suddenly gets disconnected, then the
Motor will come to a standstill.
Motor will continue to run at the same speed with line current unchanged.
Motor will continue to run at a slightly reduced speed with increased line current.
Rotor currents will have both sf and a (2-s) f component frequency where s is the slip and f is the supply frequency.
Of these statements:
1 and 4 are correct
1 and 2 are correct
3 and 4 are correct
2 and 3 are correct

Q.14:- While a 2-phase ac servomotor is in operation, if the voltage across the control field winding becomes zero, then the motor has a tendency to run as a single-phase induction motor. To prevent this
rotor having high mass moment of inertia is used for such a motor
drag cup type of light rotor with high rotor resistance is preferred
a low rotor resistance is used
The number of turns in the control field winding used is less than the main reference wingding.

Q.15:- The inertia constant of a 100 MVA, 11 KV water wheel generators is 4. The energy stored in the rotor at the synchronous speed is
(a) 400 MJ (b) 400 KJ
(c) 25 MJ (d) 25 KJ.

Q.16:- A separately excited dc generator is feeding a shunt motor. If the load torque on the motor is halved approximately.
Armature currents of both motor and generator are halved.
Armature current of motor is halved and that of generator is unaltered.
Armature current of generator is halved and that of motor is unaltered.
Armature currents of both motor and generator are unaltered.

Q.17:-Which variety of coal has lowest calorific value?
Steam coal
Bituminous coal
Lignite
Anthracite

Q.18:- The Current through an electrical conductor is 1 ampere when the temperature of the conductor is 0°C and 0.7 ampere when the temperature of the conductor is 1200°C must be
(a) 0.08 A (b) 0.16 A (C) 0.32 A (d) 0.64 A