Previous Year Questions
48 questions — organised by subject with solutions and explanations.
🎯 Practice smarter, not harder
Just sign in to unlock everything. Free for all students.
An n-channel JFET, having a pinch-off voltage ( ) of -5 V, shows a transconductance ( ) of 1 mA/V when the applied gate-to-source voltage ( ) is -3V. Its maximum transconductance (in mA/V) is
An op-amp, having a slew rate of 62.8 V/ , is connected in a voltage follower configuration. If the maximum amplitude of the input sinusoid is 10V, then the minimum frequency at which the slew rate li
For the oscillator circuit shown in figure, the expression for the time period of oscillation can be given by (where =RC)
An op-amp has an open-loop gain of and an open-loop upper cutoff frequency of 10 Hz. If this op-amp is connected as an amplifier with a closed-loop gain of 100, then the new upper cutoff frequency is
In the single-stage transistor amplifier circuit shown in figure, the capacitor is removed. Then, the ac small-signal midband voltage gain of the amplifier
Given the homogeneous state-space equaion the steady state value , given the initial state value of , is
The polar plot of a type-1, 3-pole, open-loop system is shown in figure. The closed loop system is
The asymptotic approximation of the log-magnitude versus frequency plot of a minimum phase system with real poles and one zero is shown in figure. Its transfer functions is
In case of an armature controlled separately excited dc motor drive with closedloop speed control, an inner current loop is useful because it
The output f of the 4-to-1 MUX shown in figure is
An Intel 8085 processor is executing the program given below. MVI A, 10H MVI B, 10H BACK: NOP ADD B RLC JNC BACK HLT The number of times that the operation NOP will be executed is equal to
The output of a logic gate is "1" when all its inputs are at logic "0". The gate is either
Among the following four, the slowest ADC (analog-to-digital converter) is
A sample-and-hold (S/H) circuit, having a holding capacitor of 0.1 nF, is used at the input of an ADC (analog-to-digital converter). The conversion time of the ADC is 1 sec, and during this time, the
A 240 V single-phase ac source is connected to a load with an impedance of . A capacitor is connected in parallel with the load. If the capacitor supplies 1250 VAR, the real power supplied by the sour
A passive 2-port network is in a steady-state. Compared to its input, the steady state output can never offer
Given two coupled inductors and , their mutual inductance M satisfies
A connected network of nodes has at most one branch directly connecting any pair of nodes. The graph of the network
A unit step voltage is applied at t = 0 to a series RL circuit with zero initial conditions.
In a series RLC circuit at resonance, the magnitude of the voltage developed across the capacitor
A ammeter has an internal resistance of 100 . For extending its range to measure , the shunt resistance required is of (in )
If an energy meter disc makes 10 revolutions in 100 seconds when a load of 450 W is connected to it, the meter constant (in rev/kWh) is
Resistances and have, respectively, nominal values of 10 and 5 , and tolerances of % and %. The range of values for the parallel combination of and is
The minimum number of wattmeter (s) required to measure 3-phase, 3-wire balanced or unbalanced power is
A 3-phase transformer has rating of 20 MVA, 220 kV (star) - 33 kV (delta) with leakage reactance of 12%. The transformer reactance (in ohms) referred to each phase of the L.V. delta-connected side is
Figure shows the magnetization curves of an alternator at rated armature current, unity power factor and also at no load. The magnetization curve for rated armature current, 0.8 power factor leading i
A single-phase transformer is to be switched to the supply to have minimum inrush current. The switch should be closed at
A 50 Hz balanced three-phase, Y-connected supply is connected to a balanced three phase Y-connected load. If the instantaneous phase-a of the supply voltage is and the phase-a of the load current is ,
It is desirable to eliminate 5th harmonic voltage from the phase voltage of an alternator. The coils should be short-pitched by an electrical angle of
A power system has two synchronous generators. The Governor-turbine characteristics corresponding to the generators are , Where f denotes the system frequency in Hz, and and are, respectively, the pow
The hysteresis loop of a magnetic material has an area of 5 with the scales given as 1 cm = 2 AT and 1 cm = 50 mWb. At 50 Hz, the total hysteresis loss is
An electric motor with 'constant output power' will have a torque speed characteristic in the form of a
A star-connected 440 V, 50 Hz alternators has per phase synchronous reactance of 10 . It supplies a balanced capacitive load current of 20 A, as shown in the per phase equivalent circuit of figure. It
The core flux of a practical transformer with a resistive load
In the protection of transformers, harmonic restraint is used to guard aainst
, and are steady state d-axis synchronous reactance, transient d-axis reactance and sub-transient d-axis reactance of a synchronous machine respectively. Which of the following statements is true?
The electric field (in volts/metre) at the point (1,1,0) due to a point charge of located at (-1,1,1) (coordinates in metres)is
Given the potential function in free space to be volts, the magnitude (in volts/metre) and the direction of the electric field at a point (1,-1,1), where the dimensions are in metres, are
AC-to-DC circulating current dual converters are operated with the following relationship between their triggering angles ( ).
A half-wave thyristor converter supplies a purely inductive load, as shown in figure. If the triggering angle of the thyristor is , the extinction angle will be
The main reason for connecting a pulse transformer at the output stage of a thyristor triggering circuit is to
A single-phase full-bridge voltage source inverter feeds a purely inductive load, a shown in figure, where , , , are power transistors and , , , are feedback diodes. The inverter is operated in square
A lossless radial transmission line with surge impedance loading
A 50 Hz alternator is rated 500 MVA, 20 kV, with = 1.0 per unit and per unit. It supplies a purely resistive load of 400 MW at 20 kV. The load is connected directly across the generator terminals when
The conductors of a 10 km long, single phase, two wire line are separated by a distance of 1.5m. The diameter of each conductor is 1 cm. If the conductors are of copper, the inductance of the circuit
Consider the model shown in figure of a transmission line with a series capacitor at its mid-point. The maximum voltage on the line is at the location
A 75 MVA, 10 kV synchronous generator has = 0.4 p.u. The value (in p.u.) is a base of 100 MVA, 11 kV is