Previous Paper For NPTI Assistant Electrical Engineer Exam

Please provide me question paper for NPTI Assistant Electrical Engineer Examination ?

Here I am giving you question paper for NPTI Assistant Electrical Engineer Examination in PDF file attached with it …

Some questions are given below :
1 The RMS value of the voltage u(t) =3 + 4cos (3t) is
Options
A)
 (17)
V
B) 5 V
C) 7 V
D) (3 + 2
 2
) V
Correct
Answer A


2The open loop transfer function of a unity feed back control system is given as
G(s) =
as + 1
s2
The value of ‘a’ to give a phase margin of 45° is equal to
Options
A) 0.141 B) 0.441
C) 0.841 D) 1.141
Correct
Answer C

3The armature resistance of a permanent magnet dc motor is 0.8 W. At no load,
the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm.
The efficiency of the motor while it is operating on load at 1500 rpm drawing
a current of 3.5 A from the same source will be

Options A) 48.0% B) 57.1%
C) D) 88.8% 59.2%
Correct
Answer A

4 The solution of the first order differential equation x(t) = -3x(t), x (0) = x0 is
Options
A) x (t) = x0 e-3t B) x (t) = x0 e-3
x (t) = x0 e-1/3 D) x (t) = x0 e-1 C)
Correct
Answer A

5The unit impulse response of a second order under-damped system starting
from rest is given by
c(t) = 12.5 e-6t sin 8 t, t 0
The steady-state value of the unit step response of the system is equal to
Options
A) 0 B) 0.25
C) 0.5 D) 1.0
Correct
Answer D

6A single-phase, 230 V, 50 Hz, 4 pole, capacitor-start induction motor has the
following stand-still impedances
Main winding Zm = 6.0 + j4.0 
Auxiliary winding Za = 8.0 + j6.0 
The value of the starting capacitor required to produce 90° phase difference
between the currents in the main and auxiliary windings will be
Options
A) 176.84 F B) 187.24 F
D) 280.86 F
C) 265.26 F
Correct
Answer A

7 A single-phase half-controlled rectifier is driving a separately excited dc
motor. The dc motor has a back emf constant of 0.5 V/rpm. The armature
current is 5 A without any ripple. The armature resistance is 2. The converter
is working from a 280 V, single phase ac source with a firing angle of 80°.
Under this operating condition, the speed of the motor will be
Options
A) 339 rpm B) 359 rpm
C) 366 rpm D) 386 rpm
Correct
Answer C

8The 8085 assembly language instruction that stores the content of H and L
registers into the memory locations 2050H and 2051H, respectively, is
Options
A) SPHL 2050H B) SPHL2051H
C) SHLD 2050H D) STAX 2050H
Correct
Answer C

9A 50 Hz, 4-pole, 500 MVA, 22 kV turbo-generator is delivering rated
megavolt-amperes at 0.8 power factor. Suddenly a fault occurs reducing is
electric power output by 40%. Neglect losses and assume constant power input
to the shaft. The accelerating torque in the generator in MNm at the time of the
fault will be
Options
A) 1.528 B) 1.018
C) 0.848 D) 0.509
Correct
Answer A

10The Nyquist plot of loop transfer function G(s) H(s) of a closed loop control
system passes through the point (-1, j0) in the G(s) H(s) plane. The phase
margin of the system is
Options
A) 0° B) 45°
C) 90° D) 180°
Correct
Answer D

11A 50 kW dc shunt motor is loaded to draw rated armature current at any given
speed. When driven
(i) at half the rated speed by armature voltage control and
(ii) at 1.5 times the rated speed by field control, the respective output powers
delivered by the motor are approximately.
Options
A) 25kW in (i) and 75kW in (ii) B) 25kW in (i) and 50kW in (ii)
C) 50kW in (i) and 75kW in (ii) D) 50kW in (i) and 50kW in (ii)
Correct
Answer B

12A hydraulic turbine having rated speed of 250 rpm is connected to a
synchronous generator. In order to produce power at 50 Hz, the number of
poles required in the generator are
Options
A) 6 B) 12
C) 16 D) 24
Correct
Answer D

13For the equation x(t)+3 x(t) +2x(t) = 5, the solution x (t) approaches which of
the following values as t   ?
Options
A) 0
B)
5
2
C) 5 D) 10
Correct
Answer B

14 The following motor definitely has a permanent magnet rotor
Options
A) DC commutator motor B) Brushless dc motor
C) Stepper motor D) Reluctance motor
Correct C

15A110 kV, single core coaxial, XLPE insulated power cable delivering power at
50Hz, has a capacitance of 125 nF/km. If the dielectric loss tangent of XLPE is
2 x 10-4, the dielectric power loss in this cable in W/km is
Options
A) 5.0 B) 31.7
C) 37.8 D) 189.0
Correct
Answer D

16The simultaneous application of signals x(t) and y(t) to the horizontal and
vertical plates, respectively, of an oscilloscope, produces a vertical figure-of-8
display. If P and Q are constants, and x(t) = P sin (4t + 30), then y(t) is equal to
Options
A) Q sin (4t - 30) B) Q sin (2t + 15)
C) Q sin (8t + 60) D) Q sin (4t + 30)
Correct
Answer B

17A 500 MW 3-phase Y-connected synchronous generator has a rated voltage of
21.5 kV at 0.85pf. The line current when operating at full load rated conditions
will be
Options
A) 13.43 kA B) 15.79 kA
C) 23.25 kA D) 27.36 kA
Correct
Answer B
18 Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L
load is
Options
A) zero B) constant
C) pulsating with zero average D) pulsating with non-zero average
Correct
Answer B

19 The equivalent circuit of a transformer has leakage reactances X1 , X
Options
A) X1>> X B) X1<< X
C) D) X1 X X1 X
Correct
Answer D

20 If P and Q are two random events, then the following is TRUE
Options
A) Independence of P and Q implies that
probability (P Q ) = 0
B) Probability (P Q )
Probability (P) + Probability (Q)
C) If P and Q are mutually exclusive,
then they must be independent
D) Probability (P Q )
Probability (P)
Correct
Answer D

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You need NPTI Assistant Electrical Engineer Exam model question paper, I am giving:

1 Stokes theorem connects
A) a line integral and a surface integral
B) a surface integral and a volume integral
C) a line integral and a volume integral
D) gradient of a function and its surface integral
Answer: (A)
2 A solar collector receiving solar radiation at the rate of 0.6 k W/m2 transforms it to the internal energy of a fluid at an overall efficiency of 50%. The fluid heated to 350 K is used to run a beat engine which rejects heat at 313 K. If the heat engine is to deliver 2.5 kW power, the minimum area of the solar collector required would be A) 8.33rn2
B) 16.66rn2
C) 39.68m2
D) 79.36m2
Answer: (D)

3 When the temperature of a solid metal increases,
A) strength of the metal decreaes but ductility increases
B) both strength and ductility of the metal decrease
C) both strength and ductility of the metal increase
D) strength of the metal increases but ductility decreases
Answer : (A)

4 A company produces two types of toys: P and Q. Production time of Q is twice that of P and the company has a maximum of 2000 time units per day. The supply of raw material is just sufficient to produce 1500 toys (of any type) per day. Toy type Q requires an electric switch which is available @ 600 pieces per day only. The company makes a profit of Rs. 3 and Rs. 5 on type P and Q respectively. For maximization of profits, the daily production quantities of P and Q toys should respectively be
A) 100, 500
B) 500, 1000
C) 800, 600
D) 1000, 1000
Answer : (C)

5 A spherical thermocouple junction of diameter 0.706 mm is to be used for the measurement of temperature of a gas stream. The convective heat transfer co-efficient on the bead surface is 400 W/m2K. Thermophysical properties of thermocouple material are k = 20 W/mK, C = 400 J/kg K and r = 8500 kg/m3. If the thermocouple initially tot 30°C is placed in a hot stream of 300°C, the time taken by the bead to reach 298°C, is
A) 2.35 s
B) 4.9 s
C) 14.7 s
D) 29.4 s
Answer : (B)
NPTI Question paper

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