A single-phase SCR based ac regulated is feeding power to a load consisting of  resistance and 16mH inductance. The input supply is 230V, 50Hz ac. The maximum firing angle at which the voltage across the device becomes zero all throughout and the rms value of current through SCR, under this operating condition, are

All the values of the  multi – valued complex function , where , are

Consider an LTI system with transfer function

If the input to the system is and the steady state output is , then the value of A is

Consider the differential equation

. Which of the following is a solution to this differential equation for x > 0?

Suppose the resistors and  are connected to in parallel to give an equivalent resistor R. If resistors  and  have tolerance of 1% each, the equivalent resistor R for resistors  and  will have tolerance of

Two identical coupled inductors are connected is series. The measured inductance for the two possible series connections are , Their mutual inductance in  is __________

Consider a dice with the property that the probability of a face with n dots showing up is proportional to n. The probability of the face with three dots showing up is _______.

Let x be a random variable with probability density function

The probability  is ____________.

Consider an LTI system with impulse response. If the output of the system is  then the input, x(t), is given by

A 10 kHz even-symmetric square wave is passed through a band-pass filter with center frequency at 30 kHz and 3dB pass-band of 6 kHz. The filter output is

The SOP (sum off products) form of a Boolean function is , where inputs are A, B, C, D (A is MSB, and D is LSB). The equivalent minimized expression of the function is

An input signal  is sampled with a sampling frequency of 400Hz and applied to the system whose transfer function is represented by

Where, N represents the number of samples per cycle. The output y(n) of the system under steady state is

Which of the following is an invalid state in an 8-4-2-1 Binary coded decimal counter

The sinusoidal ac source in the figure has an RMS value of . Considering all possible values of , the minimum value of  in 3 to avoid burnout of the Zener diode is __________.

A JK flip flop can be implemented by T flip-flops. Identify the correct implementation.

A system with the open loop transfer function

is connected in a negative feedback configuration with a feedback gain of unity. For the closed loop system to be marginally stable, the value of K is

Assuming the diodes to be ideal in the figure, for the output to be clipped, the input voltage  must be outside the range

Minimum of the real valued function  occurs at x equal to

The magnitude of magnetic flux density  at a point having normal distance d meters from an infinitely extended wire carrying current of I A is  (in SI units). An infinitely extended wire is laid along the x-axis and is carrying current of 4A in the +ve x direction. Another infinitely extended wire is laid along the y-axis and is carrying 2A current in the +ve direction. is permeability of free space. Assume  to be unit vectors along x, y and z axes respectively

Assuming right handed coordinate system, magnetic field intensity,  at coordinate (2,1,0) will be

To evaluate the doubled integral, we make the substitution  and . The integral will reduce to

The minimum value of the function  in the interval [-3, 3] is

The state transition matrix for the system

 is

A discrete system is represented by the difference equation

It has initial conditions. The pole locations of the system for a = 1, are

In an 8085 microprocessor, the following program is executed

Address location – Instruction

2000H              XRA A

2001H              MVI B, 04H

2003H              MVI A, 03H

2005H              RAR

2006H              DCR B

2007H              JNZ 2005

200AH              HLT

At the end of program, register A contains

The switch SW shown in the circuit is kept at position ‘1’ for a long duration. At t = 0+, the switch is moved to position ‘2’. Assuming, the voltage  across the capacitor is

A step-up chopper is used to feed a load at 400V dc from a 250V dc source. The inductor current is continuous. If the ‘off’ time of the switch is , the switching frequency of the chopper in kHz is____.

The second order dynamic system         

has the matrices P, Q and R as follows:

The system has the following controllability and observability properties.

The transistor in the given circuit should always be in active region. Take , . The maximum value of RC in  which can be used, is __________.

A parallel plate capacitor consisting two dielectric materials is shown in the figure. The middle dielectric slab is placed symmetrical with respect to the plates.

If the potential difference between one of the plates and the nearest surface of dielectric interface is 2 Volts, then the ratio  is

For the transfer function         

The values of the constant gain term and the highest corner frequency of the Bode plot respectively are

Which one of the following statements is true for all real symmetric matrices?

The SCR in the circuit shown has a latching current of 40mA. A gate pulse of 50 μs is applied to the SCR. The maximum value of R in  to ensure successful firing of the SCR is ___________.

The closed-loop transfer function of a system is . The steady state error due to unit step input is_____________.

A three phase, 100MVA, 25kV generator has solidly grounded neutral. The positive, negative and the zero sequence reactance of the generator are 0.2pu, 0.2pu and 0.05pu, respectively, at the machine base quantities. If a bolted single phase to ground fault occurs at the terminals of the unloaded generator, the fault current in amperes immediately after the fault is_______.

A fully controlled converter bridge feeds a highly inductive load with ripple free load current. The input supply  to the bridge is a sinusoidal source. Triggering angle of the bridge converter is . The input power factor of the bridge is _____________.

The voltage across the capacitor, as shown in the figure, is expressed as +

The values of and  respectively, are

A 250V dc shunt machine has armature circuit resistance of  and field circuit resistance of . The machine is connected to 250V supply mains. The motor is operated as a generator and then as a motor separately. The line current of the machine in both the cases is 50A. The ratio of the speed as a generator to the speed as a motor is_____________.

The total power dissipated in the circuit, shown in the figure, is 1kW. The voltmeter, across the load, reads 200V. The value of  is ____________

An oscillator circuit using ideal op-amp and diodes is shown in the figure.        

The time duration for +ve part of the cycle is  and for –ve part is . The value of  will be ____________.

A 20-pole alternator is having 180 identical stator slots with 6 conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generated voltage is . If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is .

Assuming full pitch, single-layer winding, the ratio  is

A synchronous generator is connected to an infinite bus with excitation voltage . The generator has a synchronous reactance of 1.1pu and is delivering real power (P) of 0.6 pu of the bus. Assume the infinite bus voltage to be 1.0pu. Neglect stator reactance. The reactive power (Q) in pu supplied by the generator to the bus under this condition is _______________.

The saw-tooth voltage waveform shown in the figure is fed to a moving iron voltmeter. Its reading would be close to_____________.

There are two generator in a power system. No-load frequencies of the generators are 51.5Hz and 51Hz, respectively. And both are having droop constant of 1 Hz/MW. Total load in the system is 2.5MW. Assuming that the generators are operating under their respective droop characteristics, the frequency of the power system in Hz in the steady state is__________.

While measuring power of a three-phase balanced load by the two-wattmeter method, the readings are 100W and 250W. The power factor of the load is_____________.

Two ammeters X and Y have resistances of  respectively and they give full-scale deflection with 150 mA and 250 mA respectively. The ranges have been extended by connecting shunts so as to give full scale deflection with 15A. The ammeters along with shunts are connected in parallel and then placed in a circuit in which the total current flowing is 15A. The current in amperes indicated in ammeter X is_________.

Assuming an ideal transformer, the Thevenin’s equivalent voltage and impedance as seen from the terminals x and y for the circuit in figure are

A single phase, 50kVA, 1000V/100V two winding transformer is connected as an autotransformer as shown in the figure.

The kVA rating of the autotransformer is ________________.

A three-phase, 4-pole, self-excited induction generator is feeding power to a load at a frequency . If the load is partially removed, the frequency becomes . If the speed of the generator is maintained at 1500 rpm in both the cases, then

For a single phase, two windings transformer, the supply frequency and voltage are both increased by 10%. The percentage changes in the hysteresis loss and eddy current loss, respectively, are        

In a constant V/f control of induction motor, the ratio V/f is maintained constant from 0 to base frequency, where V is the voltage applied to the motor at fundamental frequency f. Which of the following statements relating to low frequency operating of the motor is TRUE?

A three-phase slip-ring induction motor, provided with a commutator winding, is shown in the figure. The motor rotates in clockwise direction when the rotor windings are closed. 

If the rotor winding is open circuited and the system is made to run a rotational speed  with the help of prime-mover in anti-clockwise direction, then the frequency of voltage across slip rings is  and frequency of voltage across commutator brushes is . The values of  respectively are

A single phase induction motor draws 12 MW power at 0.6 lagging power. A capacitor is connected in parallel to the motor to improve the power factor of the combination of motor and capacitor to 0.8 lagging. Assuming that the real and reactive power drawn by the motor remains same as before, the reactive power delivered by the capacitor in MVAR is ______________.         

A three phase star-connected load is drawing power at a voltage of 0.9 pu and 0.8 power factor lagging. The three phase base power and base current are 100 MVA and 437.38 A respectively. The line-to-line load voltage in kV is______________.

Shunt reactors are sometimes used in high voltage transmission systems to

The horizontally placed conductors of a single phase line operating at 50Hz are having outside diameter of 1.6cm, the spacing between centers of the conductors is 6m. The permittivity of free space is F/m. The capacitance to ground per kilometer of each line is