For a particular intensity of incident light on a silicon pn junction solar cell, the photocurrent density is and the open-circuit voltage is 0.451 V. Consider thermal voltage to be 25 mV. If the intensity of the incident light is increased by 20 times, assuming that the temperature remains unchanged,  (in volts) will be ________

The signal , where t is in seconds, is sampled at a rate of 9000 samples per second. The sampled signal is the input to an ideal lowpass filter with frequency response H (f) as follows:  

What is the number of sinusoids in the output and their frequencies in kHz?

Consider an LTI system with magnitude response  .          

And phase response  

If the input to the system is

then the average power of the output signal y (t) is ______________

In a DRAM,

Which of the following statements is incorrect?

Which one of the following graphs shows the Shannon capacity (channel capacity) in bits of a memory less binary symmetric channel with crossover probability p ?

The residues of a function are ?

Consider a binary memoryless channel characterized by the transition probability diagram shown in the figure.         

For the system shown in the figure, Y (s)/X (s) =

A unity feedback control system is characterized by the open-loop transfer function

. The value of k for which the system oscillates at 2 rad/s is ___________

An integral I over a counterclockwise circle C is given by  If C is defined as |z| = 3, then the value of I is

The general solution of the differential equation. In terms of arbitrary constants  is

The input x(t) and the output y(t) of a continuous-time system are related as

The system is  

Consider the parallel combination of two LTI systems shown in the figure.  

The implulse responses of the systems are

If the input x(t) is a unit step signal, then the energy of y (t) is _______________j

Standard air-filled rectangular waveguides of dimensions a = 2.29 cm and b = 1.02 cm are designed for radar application. It is desired that these waveguides operate only in the dominant mode with the operating frequency at least 25% above the cutoff frequency of the mode but not higher than 95% of the next higher cutoff frequency. The range of the allowable operating frequency f is

Passengers try repeatedly to get a seat reservation in any train running between two stations until they are successful. If there is 40% chance of getting reservation in any attempt by a passenger, then the average number of attempts that passengers need to make to get a seat reserved is

Assuming that transistors are identical and have a threshold voltage of 1 V, the state of transistors are respectively        

For the circuit shown in the figure, P and Q are the inputs and Y is the output.

The logic implemented by the circuit is

Consider the state space realization

, with the initial condition,

Where u (t) denotes the unit step function. The value of

Consider the circuit shown in the figure.        

The Boolean expression F implemented by the circuit is

A programmable logic array (PLA) is shown in the figure.        

Figure I shows a 4-bit ripple carry adder realized using full adders and Figure II shows the circuit of a full-adder (FA). The propagation delay of the XOR, AND and OR gates in Figure II are 20 ns. 15 ns and 10 ns. respectively.  Assume all the inputs to the 4-bit adder are initially reset to 0.

At t = 0, the inputs to the 4-bit adder are changed to

The output of the ripple carry adder will be stable at t (in ns) = _______________

The rank of the matrix  is _______________.

A second-order LTI system is described by the following state equations.

Where  and  are the two state variables and r(t) denotes the input. The output. The system is

The transfer function of a causal LTI system  H(s) = 1/s. If the input to the system is , where u (t) is a unit step function, the system output __________.  

An n-channel enhancement mode MOSFET is biased at , where is the gate-to-source voltage,  is the drain-to-source voltage and  is the threshold voltage. Considering channel length modulation effect to be significant, the MOSFET behaves as a

Consider an n-channel MOSFET having width W, length L, electron mobility in the channel  and oxide capacitance per unit area . If gate-to-source voltage , drain-to-source voltage , threshold voltage , then the trans conductance  (in mA/V) is _____

An LTI system with unit sample response is a

A MOS capacitor is fabricated on p-type Si (Silicon) where the metal work function is 4.1  and electron affinity of Si is 4.0 eV. where  and  are the conduction band minimum and the Fermi energy levels of Si, respectively. Oxide , oxide thickness  and electronic charge C. If the measured flat band voltage of this capacitor is – 1V, then the magnitude of the fixed charge at the oxide-semiconductor interface, in , is ___________    

Two n-channel MOSFETs,  and , are identical in all respects except that the width of  is double that of . Both the transistors are biased in the saturation region of operation, but the gate overdrive voltage  of  is double that of , where  are the gate-to-source voltage and threshold voltage of the transistors, respectively. If the drain current and trans conductance of  are  respectively, the corresponding values of these two parameters for T2 are

Two conducting spheres S1 and S2 of radii a and b (b > a) respectively, are placed far apart and connected by a long, thin conducting wire, as shown in the figure.

For some charge placed on this structure, the potential and surface electric field on S1 are  and , and that on S2 are  and , respectively. Then, which of the following is CORRECT?  

If the vector function

 is irrotational, then the values of the constants , respectively, are

An electron is moving in free space with velocity towards a stationary electron far away. The closest distance that this moving electron gets to the stationary electron before the repulsive force diverts its path is ____________ .

[Given, mass of electron , charge of electron , and permittivity ]

A connection is made consisting of resistance A in series with a parallel combination of resistances B and C. Three resistors of value  are provided. Consider all possible permutations of the given resistors into the positions A, B, C, and identify the configurations with maximum possible overall resistance, and also the ones with minimum possible overall resistance. The ratio of maximum to minimum values of the resistances (up to second decimal place) is ______________.

Consider the circuit shown in the figure.

The Thevenin equivalent resistance across P-Q is _______________.[

An abrupt pn junction (located at x = 0) is uniformly doped on both p and n sides. The width of the depletion region is W and the electric field variation in the x-direction is E(x). Which of the following figures represents the electric field profile near the pn junction?

A two-wire transmission line terminates in a television set. The VSWR measured on the line is 5.8. The percentage of power that is reflected from the television set is ___________

The output  of the diode circuit shown in the figure is connected to an averaging DC voltmeter. The reading on the DC voltmeter in Volts, neglecting the voltage drop across the diode, is _________.        

In the figure, D1 is a real silicon pn junction diode with a drop of 0.7 V under forward bias condition and D2 is a Zener diode with breakdown voltage of – 6.8 V. The input is a periodic square wave of period T, whose one period is shown in the figure.        

Assuming , where  is the time constant of the circuit, the maximum and minimum values of the output waveform are respectively.

The switch in the circuit, shown in the figure, was open for a long time and is closed at t = 0.

The current i (t) (in ampere) at t = 0.5 seconds is

A unity feedback control system is characterized by the open-loop transfer function

.

The Nyquist path and the corresponding Nyquist plot of G(s) are shown in the figures below.

If , then the number of poles of the closed-loop transfer function that lie in the right-half of the s-plane is

The permittivity of water at optical frequencies is . It is found that an isotropic light source at a distance d under water forms an illuminated circular area of radius 5 m, as shown in the figure. The critical angle is

The value of d (in meter) is ___________

The state diagram of a finite state machine (FSM) designed to detect an overlapping sequence of three bits is shown in figure. The FSM has an input ‘In’ and an output ‘Out’. The initial state of the FSM is .

If the input sequence is 10101101001101, starting with the left-most bit, then the number of times will be 1 is ____

In the circuit shown, V is a sinusoidal voltage source. The current I is in phase with voltage V. The ratio  is ______________.         

The smaller angle (in degrees) between the planes x+y+z=1 and 2x – y+2z=0 is _________.

The values of the integrals   and  are

The minimum value of the function  in the interval  occurs at x = _________.

Consider the random process

where U is a zero-mean Gaussian random variable and V is a random variable uniformly distributed between 0 and 2. Assume that U and V are statistically independent. The mean value of the random process at t = 2 is _____________         

Consider the circuit shown in the figure, Assume base-to-emitter voltage  and common-base current gain  of the transistor is unity.  

The value of the collector-to-emitter voltage  (in volt) is _____________

An npn bipolar junction transistor (BJT) is operating in the active region. If the reverse bias across the base-collector junction is increased, then

In the circuit shown, transistors  are biased at a collector current of 2.6 mA, Assuming that transistor current gains are sufficiently large to assume collector current equal to emitter current and thermal voltage of 26 mV, the magnitude of voltage gain  in the mid-band frequency range is ____________ (up to second decimal place)

In the voltage reference circuit shown in the figure, the op-amp is ideal and the transistors are identical in all respects and have infinitely large values of common-emitter current gain . The collector current of the transistors is related to their base-emitter voltage by the relation , where  is the saturation current. Assume that the voltage shown in the figure is 0.7 V and the thermal voltage .

The output voltage  is ___________________

A modulating signal given by x(t)=5 sin V is fed to a phase modulator with phase deviation constant If the carrier frequency is 20 kHz, the instantaneous frequency (in kHz) at t = 0.5 ms is ____________

The unmodulated carrier power in an AM transmitter is 5 kW. This carrier is modulated by a sinusoidal modulating signal. The maximum percentage of modulation is 50%. If it is reduced to 40% then the maximum unmodulated carrier power (in kW) that can be used without overloading the transmitter is ___________

A sinusoidal message signal is converted to a PCM signal using a uniform quantizer. The required signal-to –quantization noise ratio (SQNR) at the output of the quantizer is 40 dB. The minimum number of bits per sample needed to achieve the desired SQNR is ________