UGC NET Electronics Science Exam - December 2005 : Quiz & Solutions

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Test your Preparation by solving UGC - NET 2005 (Electronics Science) Exam Question Paper :

1. The threshold voltage of an n-channel MOSFET can be increased by :
a. increasing the channel dopoint concentration
b. decreasing the channel dopoint concentration
c. reducing the gate oxide thickness
d. reducing the channel length

2. The potential difference between two points can be expressed as :
a. Volt per meter
b. Watt per ampere
c. Coulomb per Newton
d. Volt per ampere

3. Laplace tarnsform of is :
a.
b.
c.
d.

4. In a linear network the ratio of voltage excitation to current response is unaltered when position of excitation and response are interchanged. This assertion stems from :
a. principle of duality
b. principle of superposition
c. reciprocity theorem
d. equivalent theorem

5. The bandwidth of an amplifier can be increased by :
a. decreasing the capacitance of its bypass filter
b. increasing input signal frequency
c. cascading it
d. minimising its stray capacitance

6. Without the DC source, a clipper acts like a :
a. rectifier
b. clamper
c. demodulator
d. chopper

7. In order to build a mod-6 counter using three flip-flops the number of possible count sequence is :
a. 4
b. 8
c. 16
d. 28

8. The content of a 4-bit register is 1101. The register is shifted 6 times to the right with serial input being 101101. The final content of the register will be :
a. 1011
b. 0010
c. 1010
d. 0111

9. A microprocessor with a 16-bit address bus is used in linear memory selection configuration with 4 memory chips, the maximum addressable memory space is :
a. 64 k
b. 16 k
c. 8 k
d. 4 k

10. The interface chip used for data transmission between 8086 and 16 bit ADC is :
a. 8259
b. 8255
c. 8253
d. 8251

11. The FORTRAN statement A52.5, J55*A22**4/2 will calculate J as :
a. 12
b. 8.5
c. 4.5
d. 4

12. A pointer is a variable that contains as its value :
a. the dimension of another variable
b. the address of another variable
c. the size of another variable
d. the value of another variable

13. An electromagnetic wave travels in free space with electric field component . Its angular frequency w is :
a. 3e8 m/s
b. 3e8 rad/s
c. 1.5e8 rad/s
d. 1e8 rad/s

14. The behaviour of which of the following devices is governed by bulk effect :
a. Gunn diode
b. PIN diode
c. Tunnel diode
d. IMPATT diode

15. A frequency modulated signal is expressed as :
a. A cos [ wct1 K m(t) ]
b. A cos [ wct 1ϕ ]
c. A cos [ wct ]
d. A cos [ wct1K ∫m(λ) dλ ]

16. In PCM system if the quantisation levels are increased from 2 to 8, the relative bandwidth requirement will :
a. become four times
b. remain same
c. be tripled
d. be doubled

17. Optical communication systems generally use :
a. amplitude modulation
b. frequency modulation
c. phase modulation
d. intensity modulation

18. A device that exhibits a negative resistance region is :
a. P-N diode
b. UJT
c. JFET
d. BJT

19. A pyrometer is used to measure :
a. temperature
b. pressure
c. light intensity
d. low current

20. A linear discrete-time system has the characteristic equation . The system :
a. is stable
b. is marginally stable
c. is unstable
d. assessed

21. Assertion (A): At high temperature, the avalanche breakdown voltage is higher. Reason (R): At higher temperature mean free paths of electrons and holes are shorter, therefore a larger field is required to cause ionisation.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

22. Assertion (A): The Wien Bridge can be used for frequency measurements. Reason (R): The Wien Bridge uses only capacitors and resistors.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

23. Assertion (A): A demultiplexer cannot be used as a decoder. Reason (R):A demultiplexer is built using AND gates only.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

24. Assertion (A): In Intel 8085, the lower byte of address and data are multiplexed. Reason (R): This helps limit the number of external pin terminals.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

25. Assertion (A): The solution of Poisson equation is the same as the solution of Laplace equation. Reason (R): The Laplace equation is the same as Poisson equation for source free region.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

26. Assertion (A): The total emf induced in a circuit equals the time rate of change of the total magnetic flux linking the circuit. Reason (R): The induced current in a loop is always so directed as to produce a flux opposing the change in the flux density.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

27. Assertion (A): AM has better noise performance than FM. Reason (R): AM results in increase in signal power.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

28. Assertion (A): Optical communication has shifted from 1.3 mm to 1.55 mm in silica fibers. Reason (R): Dispersion and attenuation are both minimum at 1.55 mm.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

29. Assertion (A): Thyristors are preferred to power diodes in variable power rectifiers. Reason (R): Thyristors provide controlled rectification and also power loss in them is less compared to that in power diodes.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

30. Assertion (A): An important property of laser radiation is its coherence. Reason (R): Stimulated emission is the key to the operation of LASER.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

31. Consider the following semiconductor diodes : 1. Germanium diode 2. Silicon diode 3. Tunnel diode 4. Schottky diode The correct increasing order of forward voltage drop of the above diodes is :
a. 1, 3, 4, 2
b. 1, 2, 3, 4
c. 3, 4, 2, 1
d. 3, 1, 4, 2

32. In the microwave region some of the band designations are Ku, X, K and Ka. The order according to their allocated frequency band is :
a. Ku, X, K, Ka
b. X, Ku, K, Ka
c. Ka, Ku, K, X
d. K, X, Ku, Ka

33. Consider the Analog to Digital converters given below : 1. Successive approximation ADC 2. Dual Ramp ADC 3. Counter method ADC 4. Simultaneous ADC The correct sequence of the ascending order in terms of conversion times of the above ADC’s is
a. 3, 2, 4, 1
b. 2, 3, 4, 1
c. 2, 3, 1, 4
d. 3, 2, 1, 4

34. The various subsystems in an FM receiver are arranged as : 1. Mixer, RF amplifier, limiter, IF amplifier, discriminator, audio amplifier 2. RF amplifier, mixer, IF amplifier, limiter, discriminator, audio amplifier 3. RF amplifier, mixer, limiter, discriminator, IF amplifier, audio amplifier 4. Mixer, IF amplifier, limiter, audio amplifier, discriminator, RF amplifier The correct sequence of subsystems is :
a. 1
b. 2
c. 3
d. 4

35. Four main types of telephone exchanges available in India are : 1. Manual 2. Electronic 3. Strowger 4. Cross-bar The correct order in which they appeared in our country is :
a. 1, 2, 3, 4
b. 2, 1, 4, 3
c. 1, 3, 4, 2
d. 1, 4, 3, 2

36. Match the List-I with List-II :

        List-I                      List-II
    (a) BJT                       (i)   Negative resistance
    (b) MOSFET                    (ii)  High current gain
    (c) Tunnel Diode              (iii) voltage regulation
    (d) Zener Diode               (iv)  High input impedence

a. (i)(ii)(iii)(iv)
b. (ii)(iv)(i)(iii)
c. (iv)(iii)(ii)(i)
d. (iii)(i)(ii)(iv)

37. Match the List-I with List-II :

        List-I                      List-II
    (a) Linearity                 (i)   Superposition theorem
    (b) Structure                 (ii)  Norton's theorem
    (c) Equivalent circuit        (iii) Tellegen's theorem
    (d) Bilateral                 (iv)  Reciprocal theorem

a. (iii)(ii)(iv)(i)
b. (iv)(i)(ii)(iii)
c. (i)(ii)(iii)(iv)
d. (i)(iii)(ii)(iv)

38. Match the List-I with List-II :

        List-I                      List-II
    (a) Wein bridge               (i)   RF Oscillator: 2 inductance and 1 capacitance
    (b) Colpitt                   (ii)  LC Oscillator for RF: 3 capacitance and 1 inducatnce
    (c) Hartley                   (iii) RC Oscillator for audio frequecy
    (d) Clapp                     (iv)  RF Oscillator: 2 capacitor and 1 inductance

a. (i)(ii)(iii)(iv)
b. (iv)(iii)(ii)(i)
c. (ii)(iii)(iv)(i)
d. (iii)(iv)(i)(ii)

39. Match the List-I with List-II :

        List-I                      List-II
    (a) Multiplexer               (i)   Sequential memory
    (b) Demultiplexer             (ii)  Converts decimal to binary
    (c) Shift Register            (iii) Data selector
    (d) Encoder                   (iv)  Routes out many output with single input

a. (i)(ii)(iii)(iv)
b. (iv)(iii)(ii)(i)
c. (iii)(iv)(i)(ii)
d. (ii)(i)(iv)(iii)

40. Match the List-I with List-II :

        List-I                      List-II
    (a) Sign flag                 (i)   7th bit
    (b) Zero flag                 (ii)  8th bit
    (c) Parity flag               (iii) 1 bit
    (d) Carry fla                 (iv)  3rd bit

a. (ii)(i)(iv)(iii)
b. (i)(ii)(iii)(iv)
c. (iv)(ii)(i)(iii)
d. (iii)(iv)(i)(ii)

41. Match the List-I with List-II :

        List-I                      List-II
    (a) Pointer                   (i)   C Program
    (b) Dimension                 (ii)  Array
    (c) Header                    (iii) Real variable
    (d) FLOAT                     (iv)  Memory address

a. (i)(ii)(iii)(iv)
b. (iv)(ii)(i)(iii)
c. (iii)(iv)(i)(ii)
d. (ii)(i)(iv)(iii)

42. Match the List-I with List-II :

        List-I                      List-II
    (a)                     (i)   Gauss' law for electric field
    (b)                     (ii)  Ampere's law
    (c)                     (iii) Faraday's law
    (d)                     (iv)  Gauss' law for magnetic field

a. (i)(ii)(iii)(iv)
b. (iv)(i)(iii)(ii)
c. (iii)(iv)(ii)(i)
d. (ii)(iii)(i)(iv)

43. Match the List-I with List-II :

        List-I                      List-II
    (a) AM Broadcast              (i)   Multipath phenomenon
    (b) FM Broadcast              (ii)  535 - 1600 KHz
    (c) TV Broadcast              (iii) VSB modulation
    (d) Point to Point            (iv)  88 - 108 MHz

a. (i)(ii)(iii)(iv)
b. (iii)(iv)(ii)(i)
c. (ii)(iv)(iii)(i)
d. (i)(iii)(iv)(ii)

44. Match the List-I with List-II :

        List-I                      List-II
    (a) LDVT                      (i)   Pressure
    (b) Bourdon gauge             (ii)  Temperature
    (c) Strain gauge              (iii) Displacement
    (d) Thermister                (iv)  Stress

a. (i)(ii)(iii)(iv)
b. (iii)(i)(iv)(ii)
c. (iv)(i)(iii)(ii)
d. (ii)(i)(iv)(iii)

45. Match the List-I with List-II :

        List-I                      List-II
    (a) Polarisation              (i)   Bandwidth
    (b) Coherence                 (ii)  LCD
    (c) Total internal reflection (iii) Laser
    (d) Dispersion                (iv)  Optical fiber

a. (ii)(iii)(iv)(i)
b. (i)(ii)(iii)(iv)
c. (iv)(iii)(ii)(i)
d. (ii)(i)(iii)(iv)

Linked Items

[Read the passage below and answer the questions that follow based on your understanding of the passage] In 1990 Planck proposed, in order to explain the distribution of energy in the spectrum of black body, that an oscillating electron may not radiate or absorb energy continuously, as required by classic electrodynamics, but only in integer multiples of a fundamental unit called quantum. If f is the frequency of radiation, the energy of a quantum is given by E = hv where h is a constant known as Planck's constant. In 1905, Einstine went further and suggested that light, or electromagnetic radiation in general, might sometimes be regarded having a corpuscular or particle like nature. The light particles, or quanta, are called photons. Photons are peculiar in that they travel with the speed of light and have zero rest mass. What is important to notice is that can be thought of either as waves with particle like properties or as particles with wave like properties. In 1924 de Broglie generalised the idea and suggested that any moving particles with mass m and speed v, will in some experiments display wave like properties with wavelength = h/mv.

46. A quantum of visible light is called :
a. Photon
b. Proton
c. Hyperon
d. Phonon

47. A quantum will have more energy if :
a. the wavelength is longer
b. the frequency is higher
c. the amplitude is higher
d. the velocity is greater

48. The photon has its velocity in vacuum equal to :
a. 3e9 cm/s
b. 3e10 cm/s
c. 3e10 km/s
d. 9e10 cm/s

49. For an electron moving with a speed of 5.9e8 cm/sec, the accompanying wave will have a wavelength of :
a. 1.2e-8 cm
b. 1.2e-10 cm
c. 1.2e-6 cm
d. 1.2e-12 cm

50. The electron microscope works on the basis of :
a. refraction of light in lenses
b. wave like properties of electron in motion
c. pressure exerted by electron beam
d. Production of electromagnetic wave by impact of electrons on matter.

Score =

Correct Answer:

UGC NET Electronics Science Exam - December 2004 : Quiz & Solutions

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Test your Preparation by solving UGC - NET 2004 (Electronics Science) Exam Question Paper :

1. Light falls on one end of a long open-circuited n-type semiconductor bar for low level injection the hole current is predominantly to :
a. Drift
b. Diffusion
c. Both drift and diffusion
d. Length of bar

2. Under high electric fields, in a semiconductor with increasing electric field :
a. The mobility of charge carriers decreases and saturates
b. The mobility of charge carriers increases.
c. The Velocity of charge carrier increases.
None of the above

3. The action of JFET in its equivalent circuit can be represented by :
a. Current controlled current source
b. Current controlled voltage source
c. Voltage controlled current source
d. Voltage controlled voltage source

4. The function is said to have :
a. even symmetry
b. odd symmetry
c. halfwave symmetry
d. quarterwave symmetry

5. The Laplace transform of is equal to :
a.
b.
c.
d.

6. A heat sink is generally used with a transistor to :
a. increase the forward current
b. decrease the forward current
c. compensate for excessive doping
d. prevent excessive temperature rise

7. The 555 timer can be employed in : (1) A monostable multivibrator (2) A bistable multivibrator (3) An astable multivibrator Of these statements
a. 1 & 2 are correct
b. 1 & 3 are correct
c. 2 & 3 are correct
d. 1, 2 & 3 are correct

8.A toggle operation is used :
a. with a gate circuit
b. with a flip-flop
c. without a flip-flop
d. with a counter

9. A multiplexer : (1) selects one of the several inputs and transmits to a single output (2) routes the data from a single input to one of many inputs (3) converts parallel data into serial data (4) is a combination circuit. Of these statements
a. 1, 2 & 4 are correct
b. 2, 3 & 4 are correct
c. 1, 3 & 4 are correct
d. 1, 2 & 3 are correct

10. Intel 8085 supports :
a. only isolated input output
b. only memory mapped input output
c. isolated input output and memory mapped input output
d. none of these

11. An I/O processor control the flow of information between :
a. Cache memory and I/O devices
b. main memory and I/O devices
c. two I/O devices
d. cache and main memories

12. In 8085, TRAP is :
a. always maskable
b. cannot interrupt a service subroutine
c. used for catastrophic events like temporary power failure
d. lowest priority interrupt

13. Which of the following is not a high level computer programming language ?
a. FORTRAN
b. MODED
c. COBOL
d. C++ language

14. Which microwave tube uses buncher and catcher cavities :
a. Magnetron
b. Klystron
c. Reflex Klystron
d. Tunneling wave tube

15. When a plane wave propagating through free space, the direction of the field : (A) E is perpendicular to the direction of propagation (B) H is perpendicular to the direction of propagation (C) E is perpendicular to the direction of the field H . Which is correct ?
a. 1 and 2
b. 2 and 3
c. 1 and 3
d. 1, 2 and 3

16. Given a carrier frequency of 100 KHz and a modulating frequency of 5 KHz the band width of AM transmission is :
a. 5 KHz
b. 200 KHz
c. 10 KHz
d. 20 KHz

17. A PAM signal can be detected by using :
a. an ADC
b. an integrator
c. a bandpass filter
d. a highpass filter

18. Which of the following semiconductor device acts like a diode and two resistor ?
a. Triac
b. Diac
c. SCR
d. UJT

19. In a thyristor, anode current is made up of :
a. Electrons only
b. Holes only
c. both electrons and holes
d. none of these

20. Which of the following semiconductor device acts like a diode and two resistor ?
a. speed
b. high voltage
c. transmission losses
d. micro wave power

21. A piezoelectric transducer converts :
a. Pressure to voltage
b. Pressure to velocity
c. displacement
d. vibration to kinetic energy

22. A LVDT has :
a. one primary coil and two secondary coils
b. two primary coils and one secondary coil
c. one primary coil and one secondary coil
d. two primary coils and two secondary coils

23. A strain gauge is a transducer which will convert :
a. Pressure into temperature
b. Pressure into velocity
c. Pressure into change of resistance
d. force into displacement

24. CMRR (Common Mode Rejection Ratio) for a differential amplifier should be :
a. Zero
b. Unity
c. Small
d. Large

25. Which of the following diode is used for frequency tuning ?
a. Varactor diode
b. Zener diode
c. Tunnel diode
d. Gunn diode

26. Match the List-I with List-II :

        List-I                      List-II

    (a) BJT                     (i) Pinch off effect
    (b) FET                    (ii) Frequency tuning
    (c) Varactor diode        (iii) Negative resistance
    (d) Tunnel diode           (iv) Punch through effect

a. (i)(iii)(ii)(iv)
b. (i)(ii)(iii)(iv)
c. (iv)(i)(ii)(iii)
d. (i)(iv)(iii)(ii)

27. Match the List-I with List-II :

        List-I                      List-II
     (a) Former                 (i) Produces deflecting torque
     (b) Coil                  (ii) Provides base for the coil
     (c) Core                 (iii) Makes the magnetic field radia
     (d) Springs               (iv) Provides controlling torque    

a. (i)(ii)(iii)(iv)
b. (i)(ii)(iv)(iii)
c. (ii)(i)(iii)(iv)
d. (ii)(i)(iv)(iii)

28. Match the List-I with List-II :

        List-I                      List-II
    (a) Passive Network         (i) Contains electrically separable passive circuit
    (b) Active Network         (ii) Contains electrically inseparable passive circuit
    (c) Lumped Network        (iii) Contains circuit elements without energy
    (d) Distributed Network    (iv) Contains circuit elements with energy sources

a. (iii)(iv)(i)(ii)
b. (i)(ii)(iii)(iv)
c. (ii)(i)(iv)(iii)
d. (iv)(i)(ii)(iii)

29. Match the List-I with List-II :

        List-I                                          List-II
    (a) Flip-Flop can be used as latch              (i)  D Flip-Flop
    (b) Flip-Flop can be used as delayed           (ii)  Master-slave Flip-Flop
    (c) Flip-Flop does not have race problem      (iii)  JK Flip-Flop
    (d) Flip Flop can be used as shift registers   (iv)  RS Flip-Flop

a. (iv)(i)(ii)(iii)
b. (ii)(iv)(i)(iii)
c. (i)(iii)(ii)(iv)
d. (iii)(i)(iv)(ii)

30. Match the List-I with List-II :

        List-I                        List-II
     (a) Parallel comparator        (i) Null balancing type
     (b) Successive approximation  (ii) Faster converter
     (c) Dual slope               (iii) Voltage dependent conversion type
     (d) Counter type              (iv) Integrating type  

a. (ii)(i)(iii)(iv)
b. (ii)(i)(iv)(iii)
c. (i)(ii)(iv)(iii)
d. (i)(ii)(iii)(iv)

31. Match the List-I with List-II :

        List-I                      List-II
    (a) Frequency modulation       (i) Envelop detection
    (b) Double sideband           (ii) Companding
       suppressed signal carrier
    (c) PCM                      (iii) Balance modulator
    (d) Amplitude modulation      (iv) Pre-emphasis and de emphasis

a. (i)(ii)(iii)(iv)
b. (i)(ii)(iv)(iii)
c. (iv)(iii)(i)(ii)
d. (iv)(iii)(ii)(i)

32. Match the List-I with List-II :

        List-I                      List-II
    (a) RC coupling             (i) High voltage gain and impedance matching
    (b) Inductive coupling     (ii) Ability to amplify dc and low frequency signals
    (c) Transformer coupling  (iii) Minimum possible non-linear distortion
    (d) Direct coupling        (iv) Low collector supply voltage can be used

a. (iv)(i)(iii)(ii)
b. (iii)(iv)(i)(ii)
c. (i)(ii)(iii)(iv)
d. (iv)(iii)(ii)(i)

33. Match the List-I with List-II :

        List-I                       List-II
    (a) LASER                   (i) Emits light of low intensity
    (b) Solar cell             (ii) Converts light energy into electrical energy
    (c) Photo diode           (iii) Deliver powers to load
    (d) LED                    (iv) Emits light of high intensity

a. (iv)(iii)(i)(ii)
b. (iii)(iv)(ii)(i)
c. (iv)(iii)(ii)(i)
d. (iii)(iv)(i)(ii)

34. Match the List-I with List-II :

 
           List-I                             List-II
     (a) Single mode optical fiber       (i) data rate is highest
     (b) Multi mode optical fiber       (ii) data rate is medium
     (c) Graded index optical fiber    (iii) data rate is lowest
     (d) Simple glass rod optical fiber (iv) data transfer not possible

a. (i)(iii)(ii)(iv)
b. (iii)(i)(iv)(ii)
c. (ii)(iv)(iii)(i)
d. (iv)(iii)(ii)(i)

35. Match the List-I with List-II :

 
        List-I                   List-II
    (a) LVDT                (i) Pressure
    (b) Bourdon gauge      (ii) Temperature
    (c) Strain gauge      (iii) Displacement
    (d) Thermistor         (iv) Stress

a. (iv)(iii)(ii)(i)
b. (iii)(ii)(i)(iv)
c. (iv)(i)(iii)(ii)
d. (iii)(i)(iv)(ii)

36. Assertion (A) : If a semiconductor is placed in a transverse magnetic field B and an electric field E is applied across its other two faces, then it would produce an electric current I in the direction perpendicular to both B and E
Reason (R) : Hall coefficient is proportional to the mobility of charge carriers in the semiconductor.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

37. Assertion (A) : The Wein bridge can be used for frequency measurement.
Reason (R) : The Wein bridge uses only capacitors and resistors.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

38. Assertion (A) :R-2R ladder type D/A converter has a higher speed of conversion than a weighted resistance D/A convertor.
Reason (R) : R-2R ladder type D/A converter uses a smaller number of components than the weighted resistance D/A converter.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

39. Assertion (A) : Bistable multivibrator can be used as flip flop.
Reason (R) : It has two stable states.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

40. Assertion (A) : Reflex klystron is made up of a single cavity.
Reason (R) : Velocity modulation occurs in the cavity.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

41. Assertion (A) : Optical fibers have broader bandwidth to conventional copper cables.
Reason (R) : The information carrying capacity of optical fibers is limited by Rayleigh scattering loss.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

42. Assertion (A) :A monostable multivibrator can be used to alter the pulse width of a repetitive pulse train.
Reason (R) : Monostable multivibrator has a single stable state.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

43. Assertion (A) : Radio and television receivers are generally of the superheterodyne type.
Reason (R) : Wireless communication is possible by receiving signals through super heterodyne receivers.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

44. Assertion (A) :A half-adder is faster than full adder.
Reason (R) : A half adder gives only one output while a full adder gives two outputs.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

45. Assertion (A) : Stimulated emission is the key to the operation of LASER.
Reason (R) : An important property of LASER radiation is its coherence, under which is meant the correlation between the phases of oscillation at different positions in space and at various moments of time.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

Linked Items

[Read the passage below and answer the questions that follow based on your understanding of the passage] Michael Faraday was one of the greatest of all scientific researchers. In 1845 he observed experimentally a relationship between electromagnetism and light. Twenty years later James Clerk Maxwell published "A Dynamical theory of the Electro-magnetic field". Starting with four basic relationship known as Maxwell's equations, he proved mathematically that electromagnetic waves could propagate through a nonconducting medium. He predicted a value of wave velocity. In early 1880 s Heinrich Hertz succeeded in verifying Maxwell's theory of electromagnetic wave through a brilliant series of experiments. The first application of electromagnetic waves was in the field of communications. The major contribution in this respect came from Sir Jagdish Chandra Bose of Calcutta, India and Guglielmo Marconi of Italy around 1895. Sir Jagadish Chandra Bose more than a century ago generated millimeter wave by using Galena detector. With the invention of telegraphy by Samuel Morse in 1844 and telephone by Bell and Gray in 1876, a more detailed study of electrical signals on transmission lines was needed. Thanks to the pioneering work of Barkhausin and Kurz on positive -grid oscillators (1919), and Hull on smooth-bore magnetron (1921), reliable microwave sources became a reality. A tube with 20 watts output at 3 GHz was constructed by British Scientists in 1936. A year later, the Varlan brothers at Stanford conceived the idea of velocity modulation of an electron beam. Microwave tube development in the forms of travelling wave tube and Reflex Klystron in 1930 s was given great impetus by the threatening war clouds over Europe precipitated by events surrounding world war II. The early 1960 s saw the emergence of Microwave integrated circuits and solid state microwave sources. The pioneering efforts of J.B. Gunn, W.T.Read, B.C. Deloach and many others led to the successful development of Gunn effect and Impatt type oscillators. Gunn diode is based on Gunn effect and an useful microwave source of power in the frequency range of 1 GHz to 30 GHz. Gunn diode exibits NDM due to transferred electron effect. With the development of satellite communication, microwave relay stations and further growth in commercial and military radars, microwave technology turned out to be billion-dollar industry. The International MTT symposium and the Transactions of the MTT are the major sources of information on development in the theory and practice of microwave engineering.

46. Four basic relationships known as Maxwall's equation do not contain the following law :
a. Gauss law
b. Ampere's law
c. Faraday's law
d. Non existance of magnetic monopoles

47. Microwave frequency extends from :
a. 0.1 GHz to 100 GHz
b. 1 GHz to 30 GHz
c. 1 GHz to 300 GHz
d. 50 MHz to 1000 GHz

48. Millimeter wave was demonstrated by Sir J.C Bose using a solid state detector. This detector was made of :
a. Silicon
b. Germanium
c. Galena
d. Carbon

49. The idea of velocity modulation of an electron beam was used to construct :
a. Gunn diode
b. Reflex klystron
c. Magnetron
d. Carcinotron

50. Gunn diode is based on :
a. Impact ionization and avalanche multiplication effect
b. Transferred electron effect
c. Velocity modulation effect
d. Current modulation effect

Score =

Correct Answer:

Ex 7.10, 7.11, 7.12, 11.1, 11.8 & 11.10 Solution : Modern Processor Design by John Paul Shen and Mikko H. Lipasti : Solution Manual

Q.7.10: If the P6 microarchitecture had to support an instruction set that included predication, what effect would that have on the register renaming process?

Sol: Cache Address Cache Write data Predicated instructions complicate renaming, since a false predicate nullifies the register write of an instruction that otherwise writes a register.  Hence, until the predicate is known, the renamer does not know whether subsequent instructions should read from the previous or the new definition of a register written by a predicated instruction.  Hence, the renamer could stall until the predicate is determined.  Or, it could insert a move operation after the predicated op that reads both the old and new definitions of the predicated instruction’s destination register, and then copies one or the other definition to its own (nonarchitected) destination. All subsequent readers will then get renamed to the output of the move operation.

Q.7.11: As described in the text, the P6 microarchitecture splits store operations into a STA and STD pair for handling address generation and data movement.  Explain why this makes sense from a microarchitectural implementation perspective.

Sol: Logically, the STA and STD perform two different operations that interact with different control portions of the microarchitecture: the STA uses an AGEN unit to generate the address, and then resides in the MOB to resolve memory dependences against newer loads. The STD simply transfers data from the register file to the store port at commit.  Hence, it makes sense to split them.  Note that the new Banias (Centrino) designs based on the P6 core no longer split STA/STD, but treat them as a single micro-op.  This increases decode bandwidth and reduces ROB and RS occupancy.

Q.7.12: Following up on Problem 7, would there be a performance benefit (measured in instructions per cycle) if stores were not split?  Explain why or why not?

Sol: Front-end decode bandwidth would increase, while ROB and RS occupancy would decrease, permitting an effectively larger window.  Also, it is possible that commit bandwidth would increase.

Q.11.1: Using the syntax in Figure 11-2, show how to use the load-linked/store conditional primitives to synthesize a compare-and-swap operation.

Sol:  /* r1 contains compare value, r2 contains swap value */
      cmpswap: l1 r0, A
         cmp r0,r1
         bne fail
         stc r2, A
         bfail cmpswap
       fail:    ...



Q.11.8: Real coherence controllers include numerous transient states in addition to the ones shown in Figure  to support split-transaction buses. For example, when a processor issues a bus read for an invalid line (I), the line is placed in a IS transient state until the processor has received a valid data response that then causes the line to transition into shared state (S). Given a split-transaction bus that separates each bus command (bus read, bus write, and bus upgrade) into a request and response, augment the state table and state transition diagram of Figure  to incorporate all necessary transient states and bus responses. For simplicity, assume that any bus command for a line in a transient state gets a negative acknowledge (NAK) response that forces it to be retried after some delay.

Sol: 

Q.11.10:  Assuming a processor frequency of 1 GHz, a target CPI of 2, a per-instruction level-2 cache miss rate of 1% per instruction, a snoop-based cache coherent system with 32 processors, and 8-byte address messages (including command and snoop addresses)compute the inbound and outbound snoop bandwidth required at each processor node.

Sol: Outbound snoop rate = .01 miss/inst x 1 inst/2 cyc x 1 cyc/ns x 8 bytes/miss 
                                       = .04b/ns 
                                       = 40 million bytes per second

         Inbound snoop rate = 31 x 40 
                                       = 1240 million bytes per second 
                                       = 1182 MB/sec.

Ex 6.3, 6.11 &6.12 : Modern Processor Design by John Paul Shen and Mikko H. Lipasti : Solution Manual

Q.6.3: Given the dispatch and retirement bandwidth specified, how many integer ARF (architected register file) read and write ports are needed to sustain peak throughput? Given instruction mixes in Table 5-2, also compute average ports needed for each benchmark. Explain why you would not just build for the average case. Given the actual number of read and write ports specified, how likely is it that dispatch will be port-limited? How likely is it that retirement will be port-limited?

Sol: For peak throughput, 8 ARF read ports are needed at dispatch, and 4 ARF write ports are needed at retirement.  Given an average mix of 36.14% ALU which require 2 read ports and 1 write port, 1.44% multicycle ALU which require 2 read ports and 1 write port, 14.64% int loads which require one read port and one write port, 11.03% FP loads which require one read port but no write ports (only write FP), 7.18% int stores which require two read ports and no write ports, and 4.12% FP stores which require one read port.  The weighted average for 4-wide dispatch read ports is 

                       = 4 x (.3614x2 + .0144x2 + .1464x1 + .1103x1 + .0718x2 + .0412x1) 

                       = 4.77 read ports.  

The weighted average for 4-wide retirement write ports is 

                       = 4 x (.3614 + .0144 + .1464) 

                       = 2.1 write ports.

Q.6.11: The IBM POWER3 can detect up to four regular access streams and issue prefetches for future references. Construct an address reference trace that will utilize all four streams.

Sol:    Example code : for(i=0;i<10000;++i) sum += A[i] + B[i] + C[i] + D[i];

    Reference stream : A, B, C, D, A+4, B+4, C+4, D+4, A+8, B+8, C+8, D+8, etc.

Q.6.12: The IBM POWER4 can detect up to eight regular access streams and issue prefetches for future references. Construct an address reference trace that will utilize all four streams.

Sol:    Example code : for(i=0;i<10000;++i) sum += A[i] + B[i] + C[i] + D[i];

    Reference stream : A, B, C, D, A+8, B+8, C+8, D+8, A+16, B+16, C+16, D+16, etc.