(Question 1)

In the figure shown, all elements used are ideal. For timet<0, S1remained closed and S2open. At t=0, S1is opened and S2is closed. If the voltageVc2across the capacitorC2att=0 is zero, the voltage across the capacitor combination att=0+will be?

(Question 2)

Transformer and emitter follower can both be used for impedance matching at the output of an audio amplifier. The basic relationship between the input power Pinand output power Poutin both the cases is?

(Question 3)

Three generators are feeding a load of 100MW. The details of the generators are

Rating(MW)Efficiency (%)Regulation (p.u.) on 100 MVA base

Generator-1100200.02

Generator-2100300.04

Generator-3100400.03

(Question 4)

A 500MW, 21 kV, 50 Hz, 3-phase, 2-pole synchronous generator having a rated p.f=0.9, has a moment of inertia of 27.5 103kg-m2. The inertia constant (H) will be?

(Question 5)

Assume for simplicity thatNpeople, all born in April (a month of 30 days), are collected in a room. Consider the event of at least two people in the room being born on the same date of the month, even if in different years, e.g. 1980 and 1985. What is the smallestNso that the probability of this event exceeds 0.5?

(Question 6)

The Fourier Series coefficient, of a periodic signalx(t), expressed asx(t)=k=akej2pkt/Tx(t)=k=akej2pkt/Tare given bya-2= 2 -j1;a-1= 0.5 +j0.2;a0=j2;a1= 0.5 +j0.2;a2= 2 +j1;andak=0;for|k|>2ak=0;fork>2. Which of the following is true?

(Question 7)

Thez-transform of a signalx[n] is given by4z-3+ 3z-1+ 2 - 6z2+ 2z3. It is applied to a system, with a transfer functionH(z) = 3z-1- 2. 2. Let the output bey(n). Which of the following is true?

(Question 8)

A 220V, 50Hz, single-phase induction motor has the following connection diagram and winding orientations shown.MM'is the axis of the main stator winding (M1M2) andAA'is that of the auxiliary winding (A1A2). Directions of the winding axes indicate direction of flux when currents in the windings are in the directions shown. Parameters of each winding are indicated. When switchSis closed, the motor?

(Question 9)

The circuit shows an ideal diode connected to a pure inductor and is connected to a purely sinusoidal 50Hz voltage source. Under ideal conditions the current waveform through the inductor will look like?

(Question 10)

The Current Source Inverter shown in figure, is operated by alternately turning on thyristor pairs (T1,T2) and (T3,T4). If the load is purely resistive, the theoretical maximum output frequency obtainable will be?

(Question 11)

In the chopper circuit shown, the main thyristor (TM) is operated at a duty ratio of 0.8, which is much larger the commutation interval. If the maximum allowable reapplieddv/dton TMis 50 V/s, what should be the theoretical minimum value of C1? Assume current ripple through L0to be negligible?

(Question 12)

For the circuit shown, find out the current flowing through the 2 resistance. Also identify the changes to be made to double the current through the 2 resistance?

(Question 13)

The figure shows a three-phase delta connected load supplied from a 400V, 50 Hz, 3-phase balanced source. The pressure coil (PC) and current coil (CC) of a wattmeter are connected to the load as shown, with the coil polarities suitably selected to ensure a positive deflection. The wattmeter reading will be?

(Question 14)

Figure shows the extended view of a 2 pole dc machine with 10 armature conductors. Normal brush positions are shown by A and B, placed at the interpolar axis. If the brushes are now shifted, in the direction of rotation, to A' and B' as shown, the voltage waveform VA'B'will resemble?

(Question 15)

The star-delta transformer shown above is excited on the star side with a balanced, 4-wire, 3-phase, sinusoidal voltage supply of rated magnitude. The transformer is under no load condition.

With both S1 and S2 open, the core flux waveform will be?r