1.
Xr and Xa are respectively, the rms and average values of X(t) = X(t-T) and similarly ,Yr and Ya are respectively, the rms and average values of y(t) = KX (t). K and T are independent of t. Which of the following is true?
2.
A common-source amplifier with a drain resistance, R = 4.7kΩ, is powered using a 10 V power supply. Assuming that the transconductance, gm is 520 μ A/V, the voltage gain of the amplifier is closest to
3.
A single-phase, full-bridge diode rectifier fed from a 230 V, 50 Hz sinusoidal source supplies a series combination of finite resistance R and a very large inductance L. The two most dominant frequency components in the source current are !
4.
A single-phase, 4 kVA, 200 V/100 V, 50 Hz transformer with laminated CRGO steel core has rated no-load loss of 450 W. When the high-voltage winding is excited with 160 V, 40 Hz sinusoidal AC supply, the no-load losses are found to be 320 W. When the high-voltage winding of the same transformer is supplied from a 100 V, 25 Hz sinusoidal AC source, the no-load losses will be..................W(rounded off to 2 decimal places).
5.
A single-phase inverter is fed from a 100 V DC source and is controlled using a quasi-square wave modulation scheme to produce an output waveform, v(t) as shown. The angle ó is adjusted to entirely eliminate the 3rd harmonic component from the output voltage. Under this condition, for v(t), the magnitude of the 5th harmonic component as a percentage of the magnitude of the fundamental component is ..(rounded off to 2 decimal places).
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6.
Thyristor T1, is triggered at an angle α (in degree) and T₂ at angle 180° + α, in each cycle of the sinusoidal input voltage. Assume both thyristors to be ideal. To control the load power over the range 0 to 2 kW, the minimum range of variation in α is
7.
A sequence detector is designed to detect precisely 3 digital inputs, with overlapping sequences detectable. For the sequence (1, 0, 1) and input data (1,1, 0,1,0,0,1,1,0,1,0,1,1,0), what is the output of this detector?
8.
A three-phase, 50 Hz 4-pole induction motor runs at no-load with a slip of 1%. With full-load, the slip increases to 5 %. The percentage speed regulation of the motor (rounded off to 2 decimal places) is .....................
9.
A lossless transmission line with 0.2 pu reactance per phase uniformly distributed along the length of the line, connecting a generator bus to a load bus, is protected up to 80% of its length by a distance relay placed at the generator bus. The generator terminal voltage is 1 pu. There is no generation at the load bus. The threshold pu current for operation of the distance relay for a solid three phase-to-ground fault on the transmission line is closest to
10.
ax³ + bx² + cx + d is a polynomial on real x over real coefficients a, b, c, d, wherein a #0. Which of the following statements is true?
11.
Consider a linear time-invariant system whose input r(t) and output y(t) are related by the following differential equation.
12.
A three-phase cylindrical rotor synchronous generator has a synchronous reactance Xs and a negligible armature resistance. The magnitude of per phase terminal voltage is Va and the magnitude of per phase induced emf is Ea. Considering the following two statements, P and Q. P: For any three-phase balanced leading load connected across the terminals of this synchronous generator, Va is always more than Ea. Q: For any three-phase balanced lagging load connected across the terminals of this synchronous generator, Va is always less than Ea Which of the following options is correct?
13.
Which of the following statements is true about the two sided Laplace transform?
14.
A single 50 Hz synchronous generator on droop control was delivering 100 MW power to a system. Due to increase in load, generator power had to be increased by 10 MW. As a result of which, system frequency dropped to 49.75 Hz. Further increase in load in the system resulted in a frequency of 49.25 Hz. At this condition, the power in MW supplied by the generator is ................ (rounded off to 2 decimal places).
15.
The cross-section of a metal-oxide-semiconductor structure is shown schematically. Starting from an uncharged condition, a bias of +3 V is applied to the gate contact with respect to the body contact. The charge inside the silicon dioxide layer is then measured to be +Q. The total charge contained within the dashed box shown, upon application of bias, expressed as a multiple of Q (absolute value in coulombs, rounded off to the nearest integer) is ....
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1 out of 2
16.
Which of the options is an equivalent representation of the signal flow graph shown here?
17.
Out of the following options, the most relevant information needed to specify the real power (P) at the PV buses in a load flow analysis is
18.
A resistor and a capacitor are connected in series to a 10 V DC supply through a switch. The switch is closed at t=0 and the capacitor voltage is found to cross 0 V at t=0.4τ, where τ is the circuit time constant. The absolute value of percentage change required in the initial capacitor voltage, if the zero crossing has to happen at t= 0.2 τ is............ (rounded off to 2 decimal places).
19.
A single-phase, full-bridge, fully controlled thyristor rectifier feeds a load comprising a 10Ω resistance in series with a very large inductance. The rectifier is fed from an ideal 230 V, 50 Hz sinusoidal source through cables which have negligible internal resistance and a total inductance of 2.28 mH. If the thyristors are triggered at an angle α = 45°, the commutation overlap angle in degree (rounded off to 2 decimal places) is........................
20.
An 8085 microprocessor accesses two memory locations (2001 H) and (2002 H), that contain 8-bit numbers 98 H and B1 H, respectively. The following program is executed
LXI H, 2001H
MVIA, 21H
INX H
ADD M
INX H
MOV M, A
HLT
At the end of this program, the memory location 2003 H contains the number in decimal (base 10) form......
21.
Which of the following option is correct for the system shown below?
22.
A 250 V DC shunt motor has an armature resistance of 0.2Ω and a field resistance of 100Ω. When the motor is operated on no-load at rated voltage. It draws an armature current of 5 A and runs at 1200 rpm. When a load is coupled to the motor, it draws total line current of 50 A at rated voltage, with a 5 % reduction in the air-gap flux due to armature reaction. Voltage drop across the brushes can be taken as 1 V per brush under all operating conditions. The speed of the motor, in rpm, under this loaded condition, is closest to
23.
A non-ideal Si-based pi: junction diode is tested by sweeping the bias applied across its terminals from -5 V to +5 V. The effective thermal voltage Vt, for the diode is measured to be (29 ± 2) mV. The resolution of the voltage source in the measurement range is 1 mV. The percentage uncertainty (rounded off to 2 decimal places) in the measured current at a bias voltage of 0.02 V is..........................
24.
A benchtop DC power supply acts as an ideal 4 A current source as long as its terminal voltage is below 10 V. Beyond this point, it begins to behave as an ideal 10 V voltage source for all load currents going down to 0 A. When connected to an ideal rheostat, find the load resistance value at which maximum power is transferred and the corresponding load voltage and current.
2 out of 2
