| Post Name | Assistant Engineer(Instrumentation) |
|---|---|
| Department | Universities in Kerala |
| Question Paper Code | 131/2025/OL |
| Category Code | 069/2024 |
| Date of Test | 11 November 2025 |
| Exam Type | Online Examination |
| Total Questions | 100 |
1
For a 4Ć4 matrix A with the matrix multiplication operator Ć. If (n times) then which of the following are correct? i. ii.
Answer
C. Both (i) and (ii) are correct
2
Which of the following is a particular integral of the differential equation dĀ²y/dxĀ²ādy/dx=2?
Answer
D. yā=ā2x
3
Evaluate ā«ā^āā«ā^ā (eā»Źø/y) dy dx.
Answer
B. 1
4
If C is a circle |z|=2. What is the value of the integral ā®C (z+1)/((zā3)(zā1)) dz?
Answer
A. ā2Ļi
5
If the mean and variance of a binomial distribution is 3.5 and 1.05 respectively, then what is the probability of atleast two success correct to 3 decimal points.
Answer
C. 0.969
6
A wire 2.5m long is bent to a square. If the current ļ¬owing through the wire is 100A, the magnetising force at the centre of the square is:
Answer
A. 144 AT/m
7
Current carried by each of the two long parallel conductors is doubled. If their separation is also doubled, force between them would
Answer
B. increase two fold
8
The force experienced by a current carrying conductor lying parallel to a magnetic ļ¬eld is
Answer
D. zero
9
Two coils A and B are wound side by side. An emf of 0.25 V is induced in A when its flux linkage changes at 10Ā³ Wb/s. A current of 2 A in B causes a flux of 10ā»Ā³ Wb to link A. Find the mutual inductance.
Answer
C. 1.25 mH
10
Higher the self inductance of a coil,
Answer
Question Cancelled
11
A 12 volt source with an internal resistance of 1.2 ohms is connected across a wire wound resistor. maximum power will be dissipated in the resistor when its resistance is equal to:
Answer
B. 1.2 ohm
12
The Superposition theorem is essentially based on the concept of:
Answer
B. linearity
13
A cable is 300 km long and has a conductor of 0.5 cm in diameter with an insulation covering of 0.4 cm thickness. The relative permittivity of insulation in 4.5, then the total capacitance of the cable is:
Answer
B. 78
14
In a cable capacitor, the voltage gradient is maximum at the surface of the:
Answer
B. Conductor
15
In an RC circuit connected across a dc voltage source, which of the following is zero at the beginning of the transient state?
Answer
C. Capacitor voltage
16
The rms value of a half-wave rectiļ¬ed current is 10A, its value for full wave rectiļ¬cation would be
Answer
B. 14.14 A
17
A sine wave has a frequency of 50Hz. Its angular frequency is
Answer
D. 100Ļ
18
If power factor of a circuit is unity, its reactive power will be
Answer
C. zero
19
A transformer with R=0.06 ohms, X = 0.19 ohms, I = 50 Amperes, V = 200 volts at 0.8 power factor lag has an approximate voltage regulation of
Answer
D. 4%
20
In a three phase induction motor, the maximum torque is independent of
Answer
A. Rotor resistance
21
The group delay is deļ¬ned as:
Answer
C. Derivative of phase with respect to frequency with negative sign
22
If the impulse response of a continuous-time LTI system is h(t) = eā»Ā³įµ sin(5t)u(t), the system function H(s) has:
Answer
B. Complex-conjugate poles at s = ā3 Ā± j5
23
The convolution operation is:
Answer
A. Commutative, associative and distributive
24
The DTFT of a discrete sequence is {x[n]} periodic in:
Answer
B. Frequency with period 2Ļ
25
For a real odd periodic signal, the Fourier series coeļ¬cients are:
Answer
D. Purely imaginary
26
The impulse response of a real-coeļ¬cient FIR ļ¬lter with linear phase, must be:
Answer
C. Anti-symmetric or symmetric around midpoint
27
The ROC of two-sided z-transform lies:
Answer
D. A ring between the inner and outer poles
28
What is the result of the continuous convolution of two bandlimited signals?
Answer
A. A signal with bandwidth equal to sum of their bandwidths
29
For the continuous time system (y"(t)+5y'(t)+6y(t)=x(t) with zero initial conditions, the Laplace transform Y(s)/X(s) is :
Answer
B. (1/(sĀ²+5S+6))
30
The convolution theorem is applicable to:
Answer
D. Fourier transforms, Laplace transform and Z transform
31
For a unity feedback control system, internal stability requires that all closed-loop transfer functions-from every exogenous input (e.g., disturbance, noise) to every internal signal - must be stable. Which condition is suļ¬cient to guarantee the internal stability of the system?
Answer
D. The characteristic equation 1 + G(s) = 0 has all its roots in the Left Half Plane (LHP) and there must be no unstable pole-zero cancellations between the plant G(s) and the controller C(s)
32
For a mass-damper-spring mechanical system with parameters, m=1kg, B=5N.s/m and k= 100 N/m. What is the series RLC Q-factor at resonance, considering the ForceāVoltage (FāV) analogy?
Answer
C. 2
33
For a standard second order system with characteristic equation and . Then the real part of the dominant poles is
Answer
B. ā10
34
Given the block diagram with two feedback loops - inner loop Hā, outer loop Hā and forward gain G. The equivalent transfer function is:
Answer
C. G/(1+GHā+GHā)
35
For a unity-feedback control system, the open-loop transfer function is G(s) = K/[s(s + a)]. The system must satisfy: (i) maximum overshoot Mā = 16.3%; (ii) settling time tā = 2 s (2% tolerance). Given that damping ratio Ī¶ = 0.5 achieves 16.3% overshoot, determine approximate K and a.
Answer
D. a = 4, K = 16
36
The characteristic equation of a unity feedback system is given by Determine the range of k that guarantees system stability
Answer
B. 0
37
If the open-loop transfer function of a system has poles at 0, ā2, ā5 and ā10 and one open-loop zero at ā1, what is the number of branches of the Root Locus that extend to inļ¬nity?
Answer
B. 3
38
The transfer function of a lag compensator that provides a maximum phase of ā30Ā° is:
Answer
D. (1+s)/(1+3s)
39
The solution of a system described by įŗ=Ax is x(t)=eį“¬įµ. If A has eigen values (ā2, ā3) then eį“¬įµ has eigen value:
Answer
D. (eā»Ā²įµ, eā»Ā³įµ)
40
If the state matrix of a system is A=[[0,1],[0,0]] then the state transition matrix is
Answer
A. [[1,t],[0,1]]
41
Adding a dead band (neutral zone) in an ON-OFF controller:
Answer
B. Eliminates Rapid Cycling
42
In the Zeigler Nichols tuning method, the ultimate gain Ku is :
Answer
A. Gain at which oscillation just starts
43
Hydraulic actuators are known for having high power density because :
Answer
C. They operate with incompressible ļ¬uids at extremely high pressures, generating massive force from a compact actuator volume
44
The degree of interaction between loops in a multivariable process can be quantiļ¬ed by :
Answer
C. The Relative Gain Array (RGA)
45
Which controller architecture is best suited for handling the high-speed safety interlocks while maintaining regulatory control?
Answer
D. A Safety PLC (SIL/PL rated) with a dedicated, deterministic, high-priority task assigned only to the safety I/O.
46
The forward voltage drop of a silicon diode under normal conduction is approximately :
Answer
B. 0.7 V
47
The Zener diode is used primarily for
Answer
B. Voltage regulation
48
In BJT, the small-signal resistance rā is approximately
Answer
B. V_T/I_C
49
The Miller eļ¬ect causes which of the following in ampliļ¬ers?
Answer
D. Both (2) and (3)
50
The integrator op-amp circuit output for a constant input voltage is :
Answer
B. Linearly increasing
51
Slew rate of op-amp limits :
Answer
B. Maximum rate of output voltage change
52
The gain of a feedback ampliļ¬er with large loop gain AĪ² is approximately :
Answer
A. 1/Ī²
53
If the emitter resistance in a common-emitter voltage ampliļ¬er is not by passed, it will :
Answer
B. reduce the voltage gain and increase the input impedance
54
For a MOSFET based in saturation, doubling approximately causes drain current to :
Answer
B. Increase four times
55
In a practical sinusoidal oscillator :
Answer
A. the magnitude of the loop gain is slightly greater than 1 and the amplitude of the oscillation is limited by circuit parameters
56
A Wien bridge oscillator requires ampliļ¬er gain of :
Answer
C. 3
57
In a common-source MOSFET ampliļ¬er, the dominant low-frequency pole (that sets lower cut-oļ¬ frequency) is usually caused by :
Answer
B. Coupling and bypass capacitors interacting with resistances
58
A combinational circuit computes F(A,B,C,D) = Ī£m(0,2,5,7,8,10,13,15) + d(1,4,14), where d(.) are don't-care conditions. It uses two-level NAND-NAND SOP logic with true and complemented inputs available. Each NAND has delay t_pd. Variables and complements arrive at time 0, except CĢ
, which arrives at t = t_pd due to an inverter. What is the worst-case propagation delay to valid F?
Answer
A. 2t_pd
59
A quadratic equation xĀ² ā px + q = 0 has coefficients p and q expressed in base r, where p = 15įµ£ and q = 44įµ£. If one root is x = 9 in decimal, determine r.
Answer
B. 8
60
The 2's complement representation of ā37 in 8-bit is:
Answer
A. 11011011
61
A 4-bit carry look-ahead adder (CLA) has generate/propagate delays of 0.5 ns per bit and carry generation delay of 1 as per level. What is the total delay for the 4-bit addition, compared to a 4-bit ripple carry adder with 1 ns full-adder delay?
Answer
B. CLA: 3 ns, Ripple: 4 ns
62
The SNR of an ideal ADC with a full-scale sine wave input is measured as 49.8 dB. What is its resolution in bits?
Answer
A. 8 bits
63
Two 4:1 MUXes with symmetric pattern: MUX1: Iā=0, Iā=1, Iā=1, Iā=0; select Sā=A, Sā=B. MUX2: Iā=1, Iā=0, Iā=0, Iā=1; select Sā=Y, Sā=C. The output F(A, B, C) is:
Answer
B. (AāB)āC
64
The minimal Product-of-Sums expression for F(A,B,C,D)=āM(0,1,2,3,8,9,10) is :
Answer
C. (B+C)(A+B)(B+D)
65
A CMOS Schmitt-trigger inverter has V_T+ = 3.5 V and V_Tā = 1.5 V when V_DD = 5 V. If V_DD is reduced to 4 V, the new hysteresis voltage is approximately:
Answer
A. 1.6V
66
A Johnson counter with 5 ļ¬ip-ļ¬ops starts at 00000. After 7 clock pulses, the rate is:
Answer
D. 00111
67
In a ļ¬ash ADC with 5-bit resolution, the number of comparators required is :
Answer
C. 31
68
In an 8086 system, if Code Segment = 1000h and instruction Pointer = 2000h, the physical address is 12000h. After a far jump to 3000h:2000h, the new physical address is :
Answer
A. 32000h
69
A 8051 instruction that uses indexed addressing is :
Answer
B. MOVC A.@A+PC
70
In an 8085 microprocessor, a program begins with the instruction LXI SP, 3FFEh at address 0FFDh, followed by CALL 2050h at address 1000h. After executing both instruction, what is the ļ¬nal 8-bit value stored at memory location 3FFCh?
Answer
C. 03h
71
Comparison of speciļ¬c values of the input and output of an instrument with a corresponding reference standard is called :
Answer
C. Calibration
72
Hay bridge and Maxwells bridge are preferred for measuring unknown inductance with :
Answer
D. High and Low Q-values respectively
73
Linear ramp technique used in DVMs is essentially a conversion from :
Answer
D. Voltage to time
74
In a CRT, focussing of electron beam is done by :
Answer
A. Electrostatic system
75
The best method to avoid the problem of capacitive coupling in measurement systems is
Answer
B. Enclosing in an earthed metal shield
76
For the bridge circuit shown, the unknown inductance Lā is given by:
Answer
A. RāRāCā
77
Which of the following is not a component of a true rms meter?
Answer
D. RTD
78
The reason why it is important to take measurements as close to full scale as possible is because of the eļ¬ect of :
Answer
B. Limiting error
79
The reason why average responding type ac voltmeters fail to read true rms of complex ac signal is :
Answer
D. Meter is calibrated in terms of sine wave
80
A 0-100v voltmeter has an accuracy of 1% of full scale reading. The voltage measured by this meter is 50V. What is the limiting error in percentage?
Answer
C. 2%
81
A modulating signal consists of a symmetrical triangular wave having zero dc component and peak to peak voltage of 10V. It is used to amplitude modulate a carrier of peak voltage 10V. What is the modulation index?
Answer
D. 0.5
82
Which of the following is not a feature of FM compared to AM?
Answer
C. Large amount of modulating power
83
A telephone signal with a cutoļ¬ frequency of 5 KHz is digitized into 16 bit samples of Nyquist rate. Assuming raised-cosine ļ¬ltering is used with a roll-oļ¬ factor of unity, what is the transmission bandwidth required?
Answer
A. 160 KHz
84
What is the power coupled into a step-index multimode ļ¬ber whose numerical aperture is 0.2, if the SLED radiates 100 Ī¼W, assuming the radiation pattern of SLED is Lambertian?
Answer
A. 4Ī¼W
85
The lasing action is more eļ¬cient in which type of Laser Diode?
Answer
C. Quantum well type
86
Assertion (A) : In a transformer iron losses do not vary with the load current. Reason (R) : The core area is constant
Answer
A. Both (A) and (R) are individually true, but (R) is not the correct explanation of A
87
In an ac circuit, the active power is half the value of apparent power. Then the power factor of the circuit is :
Answer
C. 0.5
88
A series RLC circuit with R = 10 Ī©, X_L = 20 Ī© and X_C = 20 Ī© is connected across a 200 V AC supply. The magnitude and phase angle of voltage across the inductive coil are, respectively:
Answer
D. 400V, 90Ā°
89
A sinusoidal source of voltage 10V and frequency 50 Hz is connected to a series circuit of variable resistance R and a ļ¬xed reactance, āj0.1Ī©. The locus of the tip of the current phasor, I as R is varied from zero to inļ¬nity is :
Answer
A. A semicircle with a diameter of j100
90
The combined generator and line impedance is (4+j5)Ī©. The value of load impedance for a maximum power transfer to a load from a generator of constant generated voltage is :
Answer
B. (4āj5)Ī©
91
Assertion (A) : In a parallel RLC network, the forced resonant frequency is slightly lower than natural resonant frequency. Reason (R) : The lowest current from the source occurs at the forced resonance.
Answer
A. Both (A) and (R) are individually true, but (R) is not the correct explanation of (A)
92
Which of the following statements are associated with Thevenin's Theorem? 1. It is possible to simplify any linear circuit containing independent and dependent voltage and current sources. 2. The network is replaced by a voltage source and a series impedance remains after removing the load impedance. 3. Impedance through which current required is removed and open circuit voltage is found.
Answer
D. (1), (2) and (3)
93
Assertion (A) : Squirrel cage induction motor when connected to supply mains sometimes exhibit a tendency to run at a speed which is nearly one seventh of the synchronous speed. Reason (R) : Time harmonics in the supply.
Answer
A. Both (A) and (R) are individually true, but (R) is not the correct explanation of (A)
94
At t=0 suddenly a dc voltage of 36 V is applied to a series RL, circuit having R=12Ī© and L = 8H. The initial rate of change of current is :
Answer
D. 4.5 A/s
95
Match the similarly between magnetic and electric circuits: Column A Column B Method of speed control Performance action (a) Stator voltage control (I) Starting torque decrease (b) Rotor resistance control (II) Both speed and power factor can be controlled (c) Injection of voltage in rotor circuit (III) Maximum torque remains constant (d) Constant Volts/Hz control (IV) Starting torque increases
Answer
C. (a)-(I), (b)-(IV), (c)-(II), (d)-(III)
96
Assertion (A) : As isolating conducting sphere of charge Q and radius r is connected to a similar sphere, which is kept at a larger distance using a high resistance wire. After long time there will be heat loss. Reason (R) : They are similar sphere with same Q charge.
Answer
C. (A) is true, (R) is false
97
A long straight conductor of radius 3 mm carries a steady current uniformly distributed over its cross-section. Which of the following correctly describes the magnetic ļ¬eld at points 1 mm and 5 mm from the center of the conductor?
Answer
B. magnetic ļ¬eld increases with distance at 1 mm and decreases with distance beyond 3 mm
98
A uniformly charged, non-conducting solid sphere contains a small cavity whose center coincides with the center of the sphere. A small test charge is released from rest inside the cavity. What will be the motion of the charger?
Answer
A. it will remain at rest everywhere inside the cavity
99
A rectangular and circular loop are moving out of a uniform magnetic ļ¬eld to a ļ¬eld free region with the constant velocity v, ļ¬eld is normal to loop which of the following statements are correct :
Answer
B. induced emf is constant in case of rectangle and not a constant in case of circle
100
Assertion (A) : Self-inductance is related to inertia in mechanics Reason (R) : Electronics have mass and when the current changes they accelerate. Their mechanical inertia resists their acceleration.
Answer
C. (A) is true, (R) is false
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