Question 1

A combination of 1 F capacitor with an initial voltagec(0)=2c0=-2in series with a 100 O resistor is connected to a 20 mA ideal dc current source by operating both switches att= 0 s as shown. Which of the following graphs shown in the options approximates the voltage vsacross the current source over the next few seconds?

Question 2

x(t)xtis nonzero only forTx

Question 3

An 8-pole, 3-phase, 50 Hz induction motor is operating at a speed of 700 rpm. The frequency of the rotor current of the motor in Hz is?

Question 4

For a specified input voltage and frequency, if the equivalent radius of the core of a transformer is reduced by half, the factor by which the number of turns in the primary should change to maintain the same no load current is?

Question 5

A star connected 400 V, 50 Hz, 4 pole synchronous machine gave the following open circuit and short circuit test results:

Open circuit test: Voc= 400 V (rms, line-to-line) at field current, If= 2.3 A

Short circuit test: Isc= 10 A (rms, phase) at field current, If= 1.5 A

The value of per phase synchronous impedance in at rated voltage is?

Question 6

Three-phase to ground fault takes place at locations F1and F2in the system shown in the figure. If the fault takes place at location F1, then the voltage and the current at bus A are VF1and IF1respectively.If the fault takes place at location F2, then the voltage and the current at bus A are VF2and IF2respectively.The correct statement about voltages and currents during faults at F1and F2is?

Question 7

A 2-bus system and corresponding zero sequence network are shown in the figure. The transformersT1andT2are connected as?

Question 9

In the formation of Routh-Hurwitz array for a polynomial, all the elements of a row have zero values. This premature termination of the array indicates the presence of?

Question 10

The root locus of a unity feedback system is shown in the figure. The closed loop transfer function of the system is?

Question 11

Power consumed by a balanced 3-phase, 3-wire load is measured by the two wattmeter method. The first wattmeter reads twice that of the second. Then the load impedance angle in radians is?

Question 12

The magnitude of the mid-band voltage gain of the circuit shown in figure is (assuminghfehfeof the transistor to be 100)?

Question 13

The figure shows the circuit of a rectifier fed from a 230-V (rms), 50-Hz sinusoidal voltage source. If we want to replace the current source with a resistor so that the rms value of the current supplied by the voltage source remains unchanged, the value of the resistance (in ohms) is __________ (Assume diodes to be ideal.)?

Question 14

Figure shows four electronic switches(i), (ii), (iii)and(iv). Which of the switches can block voltages of either polarity (applied between terminals 'a' and 'b') when the active device is in the OFF state?

Question 15

Letg:[0,):[0,)g:[0,):[0,)be a function defined byg(x)=x[x]gx=x-x, where[x]xrepresents the integer part ofx. (That is, it is the largest integer which is less than or equal tox). The value of the constant term in the Fourier series expansion ofg(x)gxiss