ISRO Scientist or Engineer Electronics 2010

ISRO Scientist or Engineer Electronics 2010 - Question 1

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An LTI system has the input signal x(n). Which of the following sequence of operations is most appropriate to get output $$y(n) = x \left(n - \frac{M}{L}\right)$$.

A

Interpolation by L, Delay by M, Decimation by L

B

Delay by M,Interpolation by L, Decimation by M

C

Decimation by L, Delay by M,Interpolation by L

D

Interpolation by L, Decimation by L, delay by M

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ISRO Scientist or Engineer Electronics 2010 - Question 2

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Consider a low pass random process with a white noise power spectral density
$$ S_{x} (\omega)=\frac{N}{2}$$ where $$-2 \pi B \leq \omega \leq 2 \pi B $$
                    0 elsewhere
The Auto-correlation function $$R_{x}(\tau)$$ is

A

$$2NBsinc(2\pi B \tau)$$

B

$$\pi NBsinc(2\pi B \tau)$$

C

$$ NBsinc(2\pi B \tau)$$

D

none of the above

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ISRO Scientist or Engineer Electronics 2010 - Question 3

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Pole-zero plot of a digital filter is shown below, what is the type of filter?

A

Low Pass

B

High Pass

C

Band Stop

D

All Pass

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ISRO Scientist or Engineer Electronics 2010 - Question 4

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Determine the DTFT of the sequence $$y[n] = (n + 1) \alpha^{n} u[n], \mid \alpha \mid < 1.u[n]$$ is unit step sequence

A

$$Y(e^{j \omega }) = \frac{1}{(1 - \alpha e^{-j \omega })^2}$$

B

$$Y(e^{j \omega }) = \frac{1}{(1 + \alpha e^{-j \omega })^2}$$

C

$$Y(e^{j \omega }) = \frac{\alpha}{(1 - \alpha e^{-j \omega })^2}$$

D

none of the above

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ISRO Scientist or Engineer Electronics 2010 - Question 5

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The function f(t) has the Fourier transform g$$(\omega)$$. The Fourier transform of g(t) is

A

$$\frac{f(\omega)}{2 \pi}$$

B

$$\frac{f(- \omega)}{2 \pi}$$

C

$$2 \pi f(- \omega)$$

D

none of the above

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ISRO Scientist or Engineer Electronics 2010 - Question 6

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The purpose of Design for Test (DFT) process in ASIC design flow is

A

To capture functional errors

B

To capture manufacturing defects

C

To capture timing violations

D

For radiation mitigation

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ISRO Scientist or Engineer Electronics 2010 - Question 7

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The coupling between the two inductors is increased from zero in the circuit shown.' Which of the following statements is true?

A

The resonant frequencywill increase andthe Q will decrease

B

The resonant frequency and Q will both increase

C

The resonant frequency and Q will both decrease

D

The resonant frequency will decrease and the Q will increase

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ISRO Scientist or Engineer Electronics 2010 - Question 8

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Write a Boolean expression for Z in terms of A, B, C, D and E. You need not simplify the expression.

A

$$\overline{[\left\{(A + B).(\overline{D.E})\right\} + C}]$$

B

$$\overline{[\left\{(A.B)+(\overline{D+E})\right\}.C}]$$

C

$$[\left\{\overline{(A.B)} + (D + E)\right\}.\overline{C}]$$

D

False

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ISRO Scientist or Engineer Electronics 2010 - Question 9

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Aparallel plate capacitor of 100 pf having an air dielectric is charged to 10 kilovolts. It is then electrically isolated. The plates are pulled away from each other until the distance is ten times more than before. Estimate the energy neededto pull the plates.-

A

0.05 Joules

B

50 Joules

C

500 Joules

D

-50 Joules

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ISRO Scientist or Engineer Electronics 2010 - Question 10

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How could Schroedinger’s equation be relevant in the practical design of a CathodeRay Tube?

A

To optimize the colour quality

B

To optimize the picture sharpness

C

It is not relevant, because the CRT contains no crystalline lattice structur

D

Its effects are negligible, as the electron wavelength is very small compared to the spot size

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ISRO Scientist or Engineer Electronics 2010 - Question 11

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When compared with stripline, the major disadvantage of microstrip line is

A

Not amenable for printed circuit technique.

B

More expensive and complex to manufacture.

C

Bulkier and voluminous.

D

More likely to radiate.

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ISRO Scientist or Engineer Electronics 2010 - Question 12

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The disadvantage of single-stub matching as compared to double-stub matching,is that

A

The stub position has to be adjustable

B

Only shunt stub can be used

C

Only resistive load can be matched

D

Useful only in two wire transmission lin

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ISRO Scientist or Engineer Electronics 2010 - Question 13

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A charge $$Q_{2} = 8.854 \times 10^{-9}$$ C is located in a vaccum at $$P_{2}(2, 3, 1)$$.The force on $$Q_{2}$$ due to a charge $$Q_{1} = 4 \pi \times 10^{-3}$$ C at $$P_{1}(2, 2, 1)$$ is

A

$$a_{y} N$$

B

$$-5.4a_{x} + 6.3a_{y} - 5.4a_{z}N$$

C

$$5.4a_{x} - 6.3a_{y} - 5.4a_{z}N$$

D

None

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ISRO Scientist or Engineer Electronics 2010 - Question 14

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If a material contains $$10^{20}$$ molecules/m$$^3$$, each molecule having a moment of $$8.854 \times 10^{-27}$$ C-m parallel to an electric field of $$10^{5}$$ V/m, then its dielectric constantis

A

2.2

B

2

C

4

D

12

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ISRO Scientist or Engineer Electronics 2010 - Question 15

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If every minor of order ‘r’ of a matrix ‘A’ is zero, then rank of ‘A’is

A

greater than ‘r’

B

equal to ‘r’

C

less than or equalto ‘r’

D

less than ‘r’

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ISRO Scientist or Engineer Electronics 2010 - Question 16

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Which of the following is true

A

The product of the eigenvalues of a matrix is equal to the trace of the matrix

B

The eigenvalues of a skew-symmetric matrix are real

C

A is a nonzero column matrix and B is a nonzero row matrix, then rank of AB is one

D

A system of linear non-homogeneousequationsis consistentif and only if the rank of the coefficient matrix is less than or equalto the rank of the augmented matrix

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ISRO Scientist or Engineer Electronics 2010 - Question 17

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What is the maximum clock frequency at which following circuit can be operated | without timing violations? Assume that the Combinational logic delay is 10 ns and the clock duty cycle varies from 40% to 60 %.

A

100 MHz

B

50 MHz

C

40 MHz

D

25 MHz

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ISRO Scientist or Engineer Electronics 2010 - Question 18

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Following shift register is initially loaded with the bit pattern “1010”. After how many clock cycles will the content of shift register be “1010” again?

A

5

B

9

C

7

D

15

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ISRO Scientist or Engineer Electronics 2010 - Question 19

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Which oneofthe followingis the lowest level of abstraction for representation of a digital system?

A

$$\frac{VHDL}{Verilog}$$

B

GDS-I

C

Gate level netlist

D

SystemC

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ISRO Scientist or Engineer Electronics 2010 - Question 20

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The content of the accumulator of 8085 microprocessor after execution of the following instructions will be
MVI A, A7h
ORA A
RLC

A

FFh

B

4Fh

C

3Fh

D

CEh

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ISRO Scientist or Engineer Electronics 2010 - Question 21

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For CMOSimplementation of 2 input XORlogic gate, how many nMOSand pMOS transistors are required?

A

2 nMOSand 2 pMOS

B

3 nMOSand 3 pMOS

C

6 nMOSand 6 pMOS

D

8 nMOSand 8 pMOS

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ISRO Scientist or Engineer Electronics 2010 - Question 22

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Whichofthe following principles is applied while designing the output matching networkfor a high power Class-C amplifier?

A

Maximum Power Transfer Theorem

B

Norton’s Theorem

C

Thevenin’s Theorem

D

Power =$$\frac{(voltage)^{2}}{R_{L}}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 23

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Find the approximate output impedance of the VCCS(voltage-controlled current . source) based circuit at port Vo.

A

0.01 Ω

B

100 Ω

C

100K Ω

D

10 MΩ

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ISRO Scientist or Engineer Electronics 2010 - Question 24

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Which of the following parameters of a Silicon Schottky Diode is higher than that of a corresponding PN junction diode?

A

Forwardvoltage drop

B

Reverse recovery current

C

Reverse recovery time

D

Reverse leakage current

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ISRO Scientist or Engineer Electronics 2010 - Question 25

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Assume the intrinsic standoff ratio for the UST is 0.8 for the relaxation oscillator circuit given below. The frequency of oscillation of this circuit is approximately equal

A

1.43 kHz

B

620 Hz

C

7KHZ

D

1.6KHZ

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ISRO Scientist or Engineer Electronics 2010 - Question 26

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The approximate frequency of oscillation of the circuit shown below is

A

8.3kHz

B

16.6kHz

C

7.2KHZ

D

3.6KHZ

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ISRO Scientist or Engineer Electronics 2010 - Question 27

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A unit step voltage travels from left to right along an infinite transmissionline. It hits an inductive discontinuity at t=0. What will be the waveform immediately to the left of the discontinuity?

A

Positive spike on a unit step

B

Unit step with reduced rise time

C

Attenuated unit step

D

Magnified unit step

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ISRO Scientist or Engineer Electronics 2010 - Question 28

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A lossy open stub having a length of $$\frac{1}{32}$$ wavelength, is approximately equivalent to

A

A small capacitor in shunt with a small resistor

B

A small capacitor in shunt with a large resistor

C

A small inductor in shunt with a smallresistor

D

A large inductor in shunt with a large resistor

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ISRO Scientist or Engineer Electronics 2010 - Question 29

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Ampere's law relates

A

Electric field and Charge

B

Electric field and Current

C

Magnetic field and Current

D

Magnetic field and Charge

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ISRO Scientist or Engineer Electronics 2010 - Question 30

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Across which type of boundary doesthe electric field have a continuous tangential component?

A

Charge free boundary

B

Current free boundary

C

Any boundary

D

Charged boundary

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ISRO Scientist or Engineer Electronics 2010 - Question 31

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Laplace Transform of $$e^{at}t^{n}$$ is

A

$$\frac{n}{(s - a)^{n + 1}}$$

B

$$\frac{n!}{(s + a)^{n + 1}}$$

C

$$\frac{n!}{(s - a)^{n + 1}}$$

D

$$\frac{1}{(s - a)^{n + 1}}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 32

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For $$- \infty < x < \infty \& -1 < y < 1$$, the partial differential equation $$ x^{2} \frac{\partial^{2} u}{\partial x^{2}} + (1 - y^{2}) \frac{\partial^{2} u}{\partial y^{2}} = 0$$ is

A

parabolic

B

Hyperbolic

C

Elliptic

D

Nature connote be predicted

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ISRO Scientist or Engineer Electronics 2010 - Question 33

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A CMOSdigital circuit consumes P watts of dynamic power while operating at 20 MHz clock frequency and 5V supply. Whatwill be its dynamic power consumption if the clock frequency is increased to 40 MHz and supply voltage is decreased to 2.5V?

A

$$\frac{P}{4}$$

B

$$\frac{P}{2}$$

C

$$P$$

D

$$2P$$

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ISRO Scientist or Engineer Electronics 2010 - Question 34

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A communication channel with Additive White Gaussian Noise, has a bandwidth of 4 kHz and SNRof31dB. Its channel capacity is

A

1.6 kbps

B

20 kbps

C

32 kbps

D

256 kbps

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ISRO Scientist or Engineer Electronics 2010 - Question 35

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If the total power of an-amplitude modulated signalis 600W and the carrier power is 400W,the modulation indexis

A

0.75

B

0.5

C

0.25

D

1

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ISRO Scientist or Engineer Electronics 2010 - Question 36

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What is the advantage of Offset QPSK (OQPSK) compared to conventional QPSK?

A

Constant envelope

B

Bandwidth efficiency

C

Simple demodulator

D

All of above

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ISRO Scientist or Engineer Electronics 2010 - Question 37

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An angle modulated signal with carrier frequency $$\omega_{c} = 2 \pi \times 10^{5}$$ is described by the equation $$s(t) = 10 \cos (\omega_{c} t + 5 \sin(3000 \pi t) + 10 \sin (2000 \pi t))$$. What is the frequency deviation $$\triangle$$ f ?

A

12387.32 Hz

B

17500 Hz

C

20000 Hz

D

15000 Hz

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ISRO Scientist or Engineer Electronics 2010 - Question 38

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The Fourier transform of a signal $$x(t) = e^{-4\mid t \mid}$$

A

$$\frac{8}{16 + \omega^{2}}$$

B

$$\frac{-8}{16 - \omega^{2}}$$

C

$$\frac{4}{16 + \omega^{2}}$$

D

$$\frac{-4}{16 + \omega^{2}}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 39

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What is the output waveform $$V_{o}$$ for a sinusoidal input of peak-peak amplitude of 4V. Assume that Z1 and Z2 are two identical Zener diodes of 4.7V, and R1 = 10kohm and R2 = 20kohm.

A

Same as input

B

Sinusoidal waveform with 5.4V peak

C

Sinusoidal waveform clamped to $$\pm$$ 4.7V

D

Sinusoidal waveform clamped to $$\pm$$ 5.4V

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ISRO Scientist or Engineer Electronics 2010 - Question 40

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For a particular toroidal inductor core, the inductance value obtained for 50 Turns is $$200 \mu H$$. If two such inductors are wired in parallel, the resulting inductanceis

A

$$200 \mu H$$

B

$$50 \mu H$$

C

$$400 \mu H$$

D

$$100 \mu H$$

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ISRO Scientist or Engineer Electronics 2010 - Question 41

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The magnetic equivalent of Ohm’s Law is

A

Lenz’s Law

B

Faraday’s Law

C

Rowland’s Law

D

Maxwell’s Law

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ISRO Scientist or Engineer Electronics 2010 - Question 42

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It is required to design a class B output stage (as shown below) to deliver an average output power of 12.5W to a load of 4Ω. The power supply is selected so that $$V_{cc}$$ is 5V greater than the peak output voltage. Determine the power conversion efficiency, of the circuit.

A

48%

B

50%

C

52%

D

54%

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ISRO Scientist or Engineer Electronics 2010 - Question 43

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Which type of circuit has an input impedance as shown in this polar plot?

A

A resistance, capacitor and inductorin series

B

A resistance, capacitor and inductor in parallel

C

A resistance in shunt with a series combination of an inductor and a capacitor

D

A resistance in series with a shunt combination of an inductor and a capacitor

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ISRO Scientist or Engineer Electronics 2010 - Question 44

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A coaxial transmission line carrying an RF signalis perfectly matched to the load. Consider the cross-section of the line, at a plane where the instantaneousvoltageis at its maximum value. How will the curl of the E-field vary over this cross-section?

A

Increases from the center to the outer conductor

B

Decreases from the center to the outer conductor

C

Zero everywhere

D

Constant value proportional to the RF voltage

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ISRO Scientist or Engineer Electronics 2010 - Question 45

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The continuity of the tangential field componentat the interface of two media for normal incidence of a plane wave requires

A

B

C

D

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ISRO Scientist or Engineer Electronics 2010 - Question 46

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Which modeof a circular waveguide will have the lowest attenuation?

A

$$TE_{11}, Mode$$

B

$$TM_{01}, Mode$$

C

$$TE_{21}, Mode$$

D

$$TE_{01}, Mode$$

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ISRO Scientist or Engineer Electronics 2010 - Question 47

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If $$\psi = 2x^{2}y - xz^{3}$$, then the Laplacian of $$\psi$$ is

A

$$4yz - 6xz$$

B

$$4z - 6xy$$

C

$$4y - 6xz$$

D

$$2xy - 6yz$$

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ISRO Scientist or Engineer Electronics 2010 - Question 48

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What does the following integral evaluate to?
$$\int_{0}^{\frac{\pi}{2}} \sin^{6} \theta .d \theta$$

A

$$5 \frac{\pi}{16}$$

B

$$5 \frac{\pi}{8}$$

C

0

D

$$5 \frac{\pi}{32}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 49

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A signal with two frequency components at 6 kHz and 12 kHz, is sampled at the rate of 16 kHz and then passed through a Low Passfilter having a cut-off frequency of 16 kHz. The output signalof the filter

A

is an undistorted version of the original signal

B

contains the 6 kHz component and a spurious component of 4 kHz

C

contains only the 6 kHz components

D

contains both the componentsof the original signal and two spurious components of 4 kHz and 6 kHz

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ISRO Scientist or Engineer Electronics 2010 - Question 50

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What is the greatest allowable PRF for unambiguous reception in a radar having a maximum range of 120 km?

A

1250 pps

B

2500 pps

C

1200 pps

D

5000 pps

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ISRO Scientist or Engineer Electronics 2010 - Question 51

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A microprocessor has a cache memory with access time of 2 ns and a main memory with access time of 10 ns. If the cache missratio is 0.6, what is the average memory access time?

A

6.8 ns

B

6 ns

C

5.2 ns

D

12 ns

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ISRO Scientist or Engineer Electronics 2010 - Question 52

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Consider the following assembly code for a hypothetical RISC processor with a 4-stage pipeline (Instruction Fetch, Decode/Register Read, Execute and Write).
add $$r_{1},r_{2},r_{3} \parallel r_{1} = r_{2} + r_{3}$$
sub $$r_{4},r_{1},r_{3} \parallel r_{4} = r_{1} - r_{3}$$
mul $$r_{5},r_{2},r_{3} \parallel r_{5} = r_{2} \star r_{3}$$
Identify the possible pipeline hazard and the affected instruction.

A

Read after write hazard during mul

B

Read after write hazard during sub

C

Read after write hazard during add

D

Write after write hazard during mul

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ISRO Scientist or Engineer Electronics 2010 - Question 53

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A zero memory source emits six messages with probabilities 0.3, 0.25, 0.15, 0.12, 0.1 and 0.08. If binary Huffmancodingis used, what will be the average code length?

A

2.45 bits

B

3.45 bits

C

2.54 bits

D

3.54 bits

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ISRO Scientist or Engineer Electronics 2010 - Question 54

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In the circuit given below, assume that $$V_{cc}= 15V; Z_{1}, Z_{2}, Z_{3} \& Z_{4}$$ are identical zener diodes with breakdownvoltage of 5V; $$R_{1} = R_4 = 5kΩ, R_{2} = R_{3} = 10kΩ$$. Find $$V_{o}$$ when $$Q_{1}$$ is OFF.

A

7.5 V

B

5 V

C

10 V

D

8.33V

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ISRO Scientist or Engineer Electronics 2010 - Question 55

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Assume that $$V_{i}= 2V; R_{3} = 10Ω; \beta$$ of $$Q_{1} = 50; V_{cc} = 15V$$. Find $$I_{out}$$.

A

3.92mA

B

4mA

C

6.84mA

D

2.8mA

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ISRO Scientist or Engineer Electronics 2010 - Question 56

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A sample and hold amplifier is connected to an ADC. The acquisition time of the sample and hold amplifier is 10 usec and the conversion time of the ADCis 15 psec. What is the highest possible data rate?

A

100 ksamples

B

400 ksamples

C

40 ksamples

D

66 ksamples

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ISRO Scientist or Engineer Electronics 2010 - Question 57

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In an inverting OP-AMP,the input bias currentis -1$$\mu$$A, and the input and the feedback resistances are both 1MQ. What will be the output voltage for an input voltage of 2.5V?

A

-2.5V

B

-3.0V

C

-3.5V

D

4.0V

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ISRO Scientist or Engineer Electronics 2010 - Question 58

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Which of the following devices can be used for generating a PWM signal?

A

Comparator

B

555 timer

C

Counter and magnitude comparator

D

All the above

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ISRO Scientist or Engineer Electronics 2010 - Question 59

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A microwavereceiving antenna on a satellite is pointing towards the earth. The antenna beamwidth is 50 degrees. The earth subtends 5 degreesat the satellite. What will be the noise temperature of the antenna?

A

30 degrees Kelvin

B

5 degrees Kelvin

C

300 degrees Kelvin

D

1000 degrees Kelvin

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ISRO Scientist or Engineer Electronics 2010 - Question 60

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Estimate the magnitude and phase of the element $$S_{11}$$ of the S-matrix of the circuit shown below. Assume an operating frequency of 25 MHz.

A

$$25 \angle 180^\circ $$

B

$$25 \angle 0^\circ $$

C

$$0.33 \angle 180^\circ $$

D

$$0.33 \angle 0^\circ $$

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ISRO Scientist or Engineer Electronics 2010 - Question 61

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The electric field measured in the far field of an antenna at a distance of 50m is 1 $$\frac{V}{m}$$. The average powerdensity at a distance of 500m from the antenna is

A

$$26.6 \mu$$ W/m$$^2$$

B

$$0.1 \mu$$ W/m$$^2$$

C

$$10 \mu$$ W/m$$^2$$

D

$$13.3 \mu$$ W/m$$^2$$

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ISRO Scientist or Engineer Electronics 2010 - Question 62

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A quarter wave monopole antennais situated above a perfectly conducting ground plane.It is driven by a 50V source at 500MHz through an internal impedance of 63.5Ω . The average powerradiated by the antennais

A

39.37 W/m$$^2$$

B

4.56 W/m$$^2$$

C

68.49 W/m$$^2$$

D

45.6 W/m$$^2$$

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ISRO Scientist or Engineer Electronics 2010 - Question 63

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Directional derivative of $$U = 2x^{3}y - 3y^{2}z$$ at P(1, 2, -1) in a direction towards Q(3, -1, 5) is

A

$$\frac{-90}{7}$$

B

$$\frac{30}{7}$$

C

$$\frac{90}{49}$$

D

None of the above

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ISRO Scientist or Engineer Electronics 2010 - Question 64

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Consider the equation Re(1/z)=c, where z is a complex number,c is a nonzero constant and Re( ) represents the real part. The equation describes a

A

Straight line

B

Parabola

C

Circle

D

Noneof the above

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ISRO Scientist or Engineer Electronics 2010 - Question 65

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How many adders are required to realize a 256 point radix-2 FFT using decimation-in-time?

A

256

B

1024

C

4096

D

2048

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ISRO Scientist or Engineer Electronics 2010 - Question 66

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A uniformly distributed randomsignal x[n] with mean $$m_{x} = 2$$ and variance $$\sigma_{x}^{2} = 3$$, is passed through a 3-point moving-averagefilter having an impulse response $$\left\{h[n]\right\}=\left\{\frac{1}{3},\frac{1}{3},\frac{1}{3}\right\}$$ What will be the mean andvariance of output?

A

$$m_{y}=2, \sigma_{y}^{2}=1$$

B

$$m_{y}=2, \sigma_{y}^{2}=3$$

C

$$m_{y}=1, \sigma_{y}^{2}=1$$

D

$$m_{y}=3, \sigma_{y}^{2}=3$$

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ISRO Scientist or Engineer Electronics 2010 - Question 67

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A sine waveis applied to a balanced modulator. The peak output envelope poweris 1000 times the minimum output envelope power. Estimate the carrier suppression in
dBc.

A

24 dBc

B

30 dBc

C

36 dBc

D

40 dBc

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ISRO Scientist or Engineer Electronics 2010 - Question 68

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Consider a single error correcting (7, 4) cyclic code with generator matrix $$g(x) = x^3 + x^{2} + 1$$. Whatwill be the transmitted data if received vector r is 1101101?

A

1100

B

1010

C

0001

D

1110

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ISRO Scientist or Engineer Electronics 2010 - Question 69

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Consider a Golay’s (23,12) codewith t bits of error correction capability. For what value of t will the codeexactly satisfy the Hamming bound ?

A

2

B

3

C

4

D

5

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ISRO Scientist or Engineer Electronics 2010 - Question 70

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The maximum range of a monostatic Radar is R. If a target having a Radar cross section of $$10m^{2}$$ exists at $$\frac{R}{2}$$ what should be the target cross-section at $$\frac{3R}{2}$$ to result in an equalsignal strength at the Radar?

A

90 $$m^{2}$$

B

270 W/m$$^2$$

C

810 $$m^2$$

D

30 W/m$$^2$$

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ISRO Scientist or Engineer Electronics 2010 - Question 71

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Theelectric field intensity at a distance of 10km from an antenna having a directive gain of 10dB andradiating a total power of 60kW is

A

0.6 V/m

B

1.2 V/m

C

0.36 V/m

D

$$13.3 \mu W/m^2$$

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ISRO Scientist or Engineer Electronics 2010 - Question 72

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What is the characteristic impedance of a coaxial transmission line having inner conductor radius of Imm, outer conductor radius of 2mm anddielectric constant of 4.0?

A

50 ohm

B

60 ohm

C

20.62 ohm

D

none

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ISRO Scientist or Engineer Electronics 2010 - Question 73

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Animpedance of -10 — j2 ohmsis connected to another impedance of 45 + j5 ohms through a transmission line having a characteristic impedance of 50 ohms. Assess the stability of this circuit

A

Highly stable

B

Stability cannot be determined from the given information

C

Highly unstable

D

Marginally unstable

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ISRO Scientist or Engineer Electronics 2010 - Question 74

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A transmission line of characteristic impedance 75 ohms is terminated with an impedance of 50 ohms. The line length is increased from zero. What will be the locus of the input impedance at the other end of the line? (N.B. : Reference impedance of Smith Chart = 50 Ohms)

A

Locus [A]

B

Locus [B}

C

Locus [C}

D

Locus [D]

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ISRO Scientist or Engineer Electronics 2010 - Question 75

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The value of the integral $$\int \frac{\sin Z}{Z^{3}} .dz$$ around the circle $$\mid Z \mid = 2$$ is

A

1

B

0

C

$$-\frac{1}{2}$$

D

$$\frac{1}{2}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 76

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Which of the following functions have a jump discontinuity at x = 0

A

$$g(x) = \ln \mid x \mid$$

B

$$g(x) = \frac{1}{x^{2}}$$

C

$$\begin{cases}\frac{\sin(x)}{x} & x \neq 0\\0 & x = 0\end{cases}$$

D

None of the above

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ISRO Scientist or Engineer Electronics 2010 - Question 77

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What would be the output of the following circuit, if a positive going unipolar pulse with an amplitude greater than $$V_ref$$, is applied at the input?

A

$$V_{o}$$ will go high momentarily and return to low

B

$$V_{o}$$ will go low momentarily and return to high

C

$$V_{o}$$ will go high and remain high

D

$$V_{o}$$ will not change its previous state

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ISRO Scientist or Engineer Electronics 2010 - Question 78

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What is the output voltage across the 900 ohm load in the circuit given below?.

A

10V

B

14.67 V

C

20 V

D

9.67 V

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ISRO Scientist or Engineer Electronics 2010 - Question 79

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What is the transfer function of the network given below?

A

$$\frac{s+1}{2s+1}$$

B

$$\frac{1}{1+s}$$

C

$$\frac{1}{2s+1}$$

D

$$\frac{1}{s^{2}+2s+1}$$

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ISRO Scientist or Engineer Electronics 2010 - Question 80

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A voltage regulator having $$V_{ref}$$=1.25V needs to generate 5V output. Assumethat $$I_{adj}$$ = 100nA and $$R_{1}$$ = 10kohm. What should be value of $$R_{2}$$?

A

30 kohm

B

33.33 kohm

C

16.66kohm

D

22.22 kohm

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