CBSE NET Electronic-Science September-2013 Solved Paper II

  1. The p-n junction diode is a

    1. Passive device

    2. Vacuum device

    3. Unilateral device

    4. Bilateral device

    Answer: c

  2. A semiconductor has ______ temperature co-efficient of resistance

    1. Zero

    2. Positive

    3. Negative

    4. One

    Answer: c

  3. A JFET has

    1. One built-in diode

    2. Two built-in diode

    3. Three built-in diode

    4. Four built-in diode

    Answer: b

  4. The superposition theorem is essentially based on the concept of

    1. Quality

    2. Linearity

    3. Reciprocity

    4. Non-linearity

    Answer: b

  5. A counter that counts in binary from 0000 to 1010 is known as

    1. Binary counter

    2. Decade counter

    3. BCD counters

    4. Mod-10 counter

    Answer: a

  6. A digital multiplexer is a/an

    1. Combinational circuit

    2. Sequential circuit

    3. Amplifier

    4. Memory device

    Answer: a

  7. An 8086 has how many number of flags?

    1. 5

    2. 7

    3. 9

    4. 11

    Answer: c

  8. In 8085, microprocessor, the register which holds the address of the next instruction to be executed is

    1. Instruction registers

    2. Stack pointer

    3. Temporary register

    4. Program counter

    Answer: d

  9. The Pentium III processor is a

    1. 16 bit processor

    2. 32 bt processor

    3. 64 bit processor

    4. 128 bit processor

    Answer: c

  10. Demodulation is a process

    1. Done at the transmitter

    2. Of filtering the carrier

    3. Of removing the sidebands

    4. Similar to modulation

    Answer: b

  11. The terms frequency pushing and pulling are related to

    1. Reflex Klystron

    2. Two cavity klystron

    3. Pulsed radar system

    4. Magnetron

    Answer: d

  12. Out of the following memory types, one that is volatile is

    1. Magnetic disc

    2. Ferrite core

    3. Semiconductor ROM

    4. Semiconductor RAM

    Answer: d

  13. When Q of an antenna increases, the bandwidth

    1. Increases

    2. Decreases

    3. Stays constant equal to zero

    4. Stays constant equal to unity

    Answer: d

  14. The value of intrinsic-stand-off ratio of UJT should be

    1. >1

    2. <1

    3. 0 (zero)

    4. 10

    Answer: b

  15. In a normal ECG waveform which wave has the maximum amplitude?

    1. P wave

    2. R wave

    3. Q wave

    4. T wave

    Answer: b

  16. The output impedance in an ideal Op-Amp is

    1. Zero

    2. 20 Ω

    3. 60 Ω

    4. Infinity

    Answer: a

  17. What will be the output of the following statements? int a = 5, b = 2, c = 10, i = a > b Void main () {print f ( “hello” ); main (); }

    1. 1

    2. 2

    3. Infinite number of times

    4. 10

    Answer: c

  18. Which data communication method is used for sending data in both directions at the same time?

    1. Super duplex

    2. Simplex

    3. Half duplex

    4. Full duplex

    Answer: d

  19. The highest data rate in fiber optic communication occurs in

    1. Single-mode fiber

    2. Graded-index fiber

    3. Multimode fiber

    4. Co-axial cable

    Answer: a

  20. Routh's array for a system is given below: S4 1 3 5 S3 1 2 9 S2 1 5 S1 –3 S0 5 The system is

    1. Stable

    2. Unstable

    3. Marginally stable

    4. Conditionally stable

    Answer: b

    • Assertion (A): In a common base amplifier voltage gain is more than 1.
    • Reason (R): In a common base amplifier current gain is less than 1.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: a

    • Assertion (A): Op-Amp is used for amplification of weak signals.
    • Reason (R): To rectify EMG signals, precision rectifiers are used.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: b

    • Assertion (A): Gray is unweighted code.
    • Reason (R): Gray code is not self-complementary.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: a

    • Assertion (A): TDM and FDM accomplish the same end by different means.
    • Reason (R): FDM involves simpler instrumentation as compared to TDM.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: c

    • Assertion (A): A SSB system is used for broadcasting applications.
    • Reason (R): The saving of power in SSB system is ≥ 75%.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: f

    • Assertion (A): Dual slope A/Dconverter is the most preferred conversion technique employed in most of the digital multimeters.
    • Reason (R): Dual slope A/D converter provides high accuracy while at the same time suppresses the HUM effect on the input signal.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: a

    • Assertion (A): The system of propagation in waveguides is in accordance to field theory.
    • Reason (R): The system of propagation in transmission line is in accordance with circuit theory.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: b

    • Assertion (A): For a function to be odd f (–x) = –f (x).
    • Reason (R): If a function is odd, its Fourier series only contains cosine terms.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: c

    • Assertion (A): A number of thyristors operating in parallel cannot share a common heat sink.
    • Reason (R): For simultaneous firing of the thyristor opto isolators may be employed in the gate driving circuit.
    1. Both A and R are true and R is the correct explanation of (A).

    2. Both A and R are true, but R is not the correct explanation of (A).

    3. A is true and R is false.

    4. A is false and R is true.

    Answer: d

  21. Consider the following devices:

    1. RTL

    2. High Speed TTL

    3. ECL

    4. CMOS

    The correct sequence of ther decrease in power dissipation is

    1. 3, 1, 2, 4

    2. 3, 1, 4, 2

    3. 1, 3, 2, 4

    4. 3, 2, 4, 1

    Answer: a

  22. Arrange the following in terms of their increasing conductivity:

    1. Copper

    2. Steel

    3. Leather

    4. Rubber

    The correct sequence is

    1. 4, 3, 2, 1

    2. 4, 3, 1, 2

    3. 3, 4, 2, 1

    4. 2, 1, 3, 4

    Answer: a

  23. Following are the EM waves:

    1. Red colour light

    2. Blue colour light

    3. Microwaves

    4. X-rays

    The correct sequence of decreasing order of wavelength is

    1. 2, 4, 3, 1

    2. 1, 3, 2, 4

    3. 3, 1, 4, 2

    4. 3, 1, 2, 4

    Answer: d

  24. Following are the process steps to fabricate an IC:

    1. Crystal growth

    2. Epitaxial growth

    3. Photo etching

    4. Diffusion

    5. Vacuum evaporation of Aluminium

    The correct sequence of fabrication is

    1. 1, 5, 3, 4, 2

    2. 1, 2, 3, 4, 5

    3. 1, 3, 2, 4, 5

    4. 1, 2, 4, 3, 5

    Answer: b

  25. Following are the modulation/multiplexing techniques:

    1. AM

    2. FM

    3. CDMA

    4. WDM

    The correct sequence of carrier frequency in decreasing order is

    1. 1, 2, 3, 4

    2. 4, 3, 1, 2

    3. 4, 3, 2, 1

    4. 3, 4, 2, 1

    Answer: c

  26. Match the following:

    List-I List-II
    1. LED

    2. APD

    3. Tunnel diode

    4. Laser

    1. Heavily doped

    2. Coherent radiation

    3. Spontaneous emission

    4. Current gain

    • A
    • B
    • C
    • D
      • 2
      • 1
      • 3
      • 4
      • 4
      • 3
      • 2
      • 1
      • 3
      • 4
      • 1
      • 2
      • 3
      • 2
      • 1
      • 4

    Answer: c

  27. Match the following:

    List-I List-II
    1. Cassegrain antenna

    2. Yagi antenna

    3. Parabolic reflector antenna

    4. Loop antenna

    1. Large B. W.

    2. Direction finding

    3. Radar

    4. Directional transmission

    • A
    • B
    • C
    • D
      • 1
      • 4
      • 2
      • 3
      • 3
      • 1
      • 4
      • 2
      • 2
      • 4
      • 3
      • 1
      • 3
      • 2
      • 4
      • 1

    Answer: b

  28. Match the lists:

    List-I (Band gap in eV) List-II (Materials)
    1. 0.67

    2. 1.1

    3. 1.4

    4. 2.4

    1. Ga As

    2. Cadmium sulphate

    3. Si

    4. Ge

    • A
    • B
    • C
    • D
      • 4
      • 3
      • 1
      • 2
      • 3
      • 2
      • 1
      • 4
      • 4
      • 1
      • 3
      • 2
      • 2
      • 3
      • 1
      • 4

    Answer: a

  29. Match the following:

    List-I List-II
    1. Voltage series feedback connection

    2. Voltage shunts feedback connection

    3. Current series feedback connection

    4. Voltage series feedback connection

    1. increases input impedance

    2. Decreases the input impedance

    3. Increases the output impedance

    4. Decreases the output impedance

    • A
    • B
    • C
    • D
      • 4
      • 2
      • 3
      • 1
      • 4
      • 2
      • 1
      • 3
      • 1
      • 3
      • 4
      • 2
      • 1
      • 2
      • 3
      • 4

    Answer: d

  30. Match the following lists:

    List-I List-II
    1. Electromyogram

    2. Electrocardiogram

    3. Electroencephalogram

    4. Spirometer

    1. Tracing brain waves

    2. Tracing of muscular waves

    3. Measurement of air in lungs

    4. A record of electrical activity of heart

    • A
    • B
    • C
    • D
      • 1
      • 2
      • 3
      • 4
      • 1
      • 4
      • 3
      • 2
      • 1
      • 4
      • 2
      • 3
      • 4
      • 3
      • 1
      • 2

    Answer: c

  31. Match the following:

    List-I List-II
    1. Removes ac ripple

    2. Supplies ac input voltage

    3. Constant dc output voltage

    4. Filter choke inductor

    1. Zener diode

    2. Filter capacitor

    3. No output voltage

    4. Power transformer

    • A
    • B
    • C
    • D
      • 2
      • 4
      • 1
      • 3
      • 1
      • 4
      • 3
      • 2
      • 4
      • 1
      • 2
      • 3
      • 2
      • 3
      • 1
      • 4

    Answer: a

  32. Match the following lists:

    List-I List-II
    1. Maxwells bridge

    2. Hay's bridge

    3. Schering's bridge

    4. Weins bridge

    1. Measurement of unknown inductance

    2. Measurement of high Q of coils

    3. Precision measurement of capacitance

    4. To measure frequency

    • A
    • B
    • C
    • D
      • 1
      • 2
      • 3
      • 4
      • 4
      • 3
      • 2
      • 1
      • 4
      • 2
      • 3
      • 1
      • 1
      • 3
      • 2
      • 4

    Answer: a

  33. Match the following lists:

    List-I List-II
    1. Gamma rays

    2. Visible light

    3. Radiowaves 3.

    4. Microwaves 4.

    1. 400 − 700 nm

    2. 1 − 10 cm

    3. × 10 + 3 m

    4. × 10–11 m

    • A
    • B
    • C
    • D
      • 1
      • 2
      • 3
      • 4
      • 4
      • 3
      • 2
      • 1
      • 4
      • 1
      • 3
      • 2
      • 2
      • 3
      • 4
      • 1

    Answer: c

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

    List-I (Type of counters) List-II (No. Of flip flops required)
    1. Mod-6

    2. Mod-11

    3. Mod-31

    1. 3

    2. 4

    3. 5

    • A
    • B
    • C
      • 3
      • 2
      • 1
      • 1
      • 2
      • 3
      • 2
      • 3
      • 1
      • 3
      • 1
      • 2

    Answer: b

  35. Match the following lists:

    List-I (Units) List-II (Quantty)
    1. ps/nm/km

    2. dB/km

    3. cm2/v-s

    4. Tesla

    1. Attenuation

    2. Magnetic field

    3. Dispersion

    4. Mobility

    • A
    • B
    • C
    • D
      • 4
      • 1
      • 2
      • 3
      • 3
      • 1
      • 2
      • 4
      • 3
      • 1
      • 4
      • 2
      • 1
      • 4
      • 3
      • 2

    Answer: c

Read the paragraph and answer the questions 46 to 50:

P-i-n photodiode contains a layer of intrinsic semi-conductor material sandwiched between p-and-n regions. The depletion layer is wholly contained within the i region. Thickness of the intrinsic region can be adjusted to produce device with optimum sensitivity and frequency response. P-i-n photodiode is most common type of depletion layer photodiode.

The other classes of photodiodes, avalanche photodiodes, are reverse-biased p-n junction diodes that are operated at voltages above the breakdown voltage. Current multiplication of electron-hole pairs generated by the incident electromagnetic radiation occurs due to avalanche process. The photo multiplication factor Mpn is defined as ratio of the multiplied photocurrent Ipm to the photocurrent Ipho at voltage below breakdown where no avalanche multiplication takes place.

  1. Semiconductors are sensitive to

    1. Heat

    2. Magnetic field

    3. Light energy

    4. All of the above

    Answer: d

  2. Which of the following elements is a semiconductor?

    1. Germanium

    2. Copper

    3. Carbon

    4. Phosphorous

    Answer: a

  3. When a reverse bias is applied to a junction diode

    1. Potential barrier is lowered

    2. Majority carrier current is increased

    3. Minority carrier current is increased

    4. Potential barrier is raised

    Answer: d

  4. Photo-diode is reverse biased because

    1. Only one side is illuminated

    2. Majority swept are reverse biased across the function

    3. Reverse current is small as compared to photo current

    4. Reverse current is large as compared to photocurrent

    Answer: c

  5. Avalanche photodiodes are preferred over PIN diodes in optical communication systems because of

    1. Speed of operation

    2. Higher sensitivity

    3. Larger bandwidth

    4. Larger power handling capacity

    Answer: d