Tamil Nadu Board of Secondary EducationHSC Science Class 12th

# Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide chapter 10 - Electronics and Communication [Latest edition]

## Chapter 10: Electronics and Communication

Evaluation
Evaluation [Pages 246 - 247]

### Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide Chapter 10 Electronics and CommunicationEvaluation [Pages 246 - 247]

#### Multiple choice questions

Evaluation | Q I. 1. | Page 246

The barrier potential of a silicon diode is approximately, ____________.

• 0.7 V

• 0.3 V

• 2.0 V

• 2.2 V

Evaluation | Q I. 2. | Page 246

Doping a semiconductor result in

• The decrease in mobile charge carriers

• The change in chemical properties

• The change in the crystal structure

• The breaking of the covalent bond

Evaluation | Q I. 3. | Page 246

In an unbiased p-n junction, the majority of charge carriers (that is, holes) in the p-region diffuse into the n-region because of

• the potential difference across the p-n junction

• the higher hole concentration in p-region than that in n-region

• the attraction of free electrons of n-region

• the higher concentration of electrons in the n-region than that in the p-region

Evaluation | Q I. 4. | Page 246

If a positive half-wave rectified voltage is fed to a load resistor, for which part of a cycle there will be current flow through the load?

• 0° – 90°

• 90° – 180°

• 0° – 180°

• 0° – 360°

Evaluation | Q I. 5. | Page 246

The zener diode is primarily used as ____________.

• Rectifier

• Amplifier

• Oscillator

• Voltage regulator

Evaluation | Q I. 6. | Page 246

The principle based on which a solar cell operates is ____________.

• Diffusion

• Recombination

• Photovoltaic action

• Carrier flow

Evaluation | Q I. 7. | Page 246

The light emitted in an LED is due to

• Recombination of charge carriers

• Reflection of light due to lens action

• Amplification of light falling at the junction

• Large current capacity

Evaluation | Q I. 8. | Page 246

The barrier potential of a p-n junction depends on

(i) type of semiconductor material

(ii) amount of doping

(iii) temperature

Which one of the following is correct?

• (i) and (ii) only

• (ii) only

• (ii) and (iii) only

• (i), (ii) and (iii)

Evaluation | Q I. 9. | Page 246

To obtain sustained oscillation in an oscillator,

• Feedback should be positive

• Feedback factor must be unity

• Phase shift must be 0 or 2π

• All the above

Evaluation | Q I. 10. | Page 246

If the input to the NOT gate is A = 1011, its output is ____________.

• 0100

• 1000

• 1100

• 0011

Evaluation | Q I. 11. | Page 246

Which one of the following represents forward bias diode?

Evaluation | Q I. 12. | Page 247

The given electrical network is equivalent to

• AND gate

• OR gate

• NOR gate

• NOT gate

Evaluation | Q I. 13. | Page 247

The output of the following circuit is 1 when the input ABC is

• 101

• 100

• 110

• 010

Evaluation | Q I. 14. | Page 247

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called ____________.

• Amplitude modulation

• Frequency modulation

• Phase modulation

• Pulse width modulation

Evaluation | Q I. 15. | Page 247

The frequency range of 3 MHz to 30 MHz is used for ____________.

• Ground wave propagation

• Space wave propagation

• Sky wave propagation

• Satellite communication

Evaluation [Pages 247 - 248]

### Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide Chapter 10 Electronics and CommunicationEvaluation [Pages 247 - 248]

Evaluation | Q II. 1. | Page 247

Define forbidden energy gap.

Evaluation | Q II. 2. | Page 247

Why is temperature co-efficient of resistance negative for semiconductor?

Evaluation | Q II. 3. | Page 247

What do you mean by doping?

Evaluation | Q II. 4. | Page 247

Distinguish between intrinsic and extrinsic semiconductors.

Evaluation | Q II. 5. | Page 247

A diode is called a unidirectional device. Explain.

Evaluation | Q II. 6. | Page 247

What do you mean by leakage current in a diode?

Evaluation | Q II. 7. | Page 247

Draw the input and output waveforms of a full wave rectifier.

Evaluation | Q II. 8. | Page 247

Distinguish between avalanche breakdown and Zener breakdown.

Evaluation | Q II. 9. | Page 247

Give the Barkhausen conditions for sustained oscillations.

Evaluation | Q II. 10. | Page 247

Explain the current flow in an NPN transistor.

Evaluation | Q II. 11. | Page 247

What are logic gates?

Evaluation | Q II. 12. | Page 247

Explain the need for a feedback circuit in a transistor oscillator.

Evaluation | Q II. 13. | Page 247

Write a short note on diffusion current across the p-n junction.

Evaluation | Q II. 14. | Page 247

What is meant by biasing?

Evaluation | Q II. 14. | Page 247

Mention the types of biasing.

Evaluation | Q II. 15. | Page 247

Why can’t we interchange the emitter and collector even though they are made up of the same type of semiconductor material?

Evaluation | Q II. 16. | Page 248

Why are NOR and NAND gates called universal gates?

Evaluation | Q II. 17. | Page 248

Define barrier potential.

Evaluation | Q II. 18. | Page 248

What is rectification?

Evaluation | Q II. 19. | Page 248

List the applications of light emitting diode.

Evaluation | Q II. 20. | Page 248

Give the principle of solar cells.

Evaluation | Q II. 21. | Page 248

What is an integrated circuit?

Evaluation | Q II. 22. | Page 248

What is modulation?

Evaluation | Q II. 23. | Page 248

Define bandwidth of transmission system.

Evaluation | Q II. 24. | Page 248

What do you mean by skip distance?

Evaluation | Q II. 25. | Page 248

Evaluation | Q II. 26. | Page 248

What is mobile communication?

Evaluation | Q II. 27. | Page 248

Explain centre frequency or resting frequency in frequency modulation.

Evaluation | Q II. 28. | Page 248

Evaluation [Page 248]

### Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide Chapter 10 Electronics and CommunicationEvaluation [Page 248]

Evaluation | Q III. 1. | Page 248

Elucidate the formation of n-type extrinsic semiconductors.

Evaluation | Q III. 2. | Page 248

Explain the formation of depletion region and barrier potential in PN junction diode.

Evaluation | Q III. 3. | Page 248

Draw the circuit diagram of a half wave rectifier and explain its working.

Evaluation | Q III. 4. | Page 248

Explain the construction and working of a full-wave rectifier.

Evaluation | Q III. 5. | Page 248

What is an LED? Give the principle of its operation with a diagram.

Evaluation | Q III. 6. | Page 248

Write notes on the photodiode.

Evaluation | Q III. 7. | Page 248

Explain the working principle of a solar cell. Mention its applications.

Evaluation | Q III. 8. | Page 248

Sketch the static characteristics of a common emitter transistor and bring out the essential features of input and output characteristics.

Evaluation | Q III. 9. | Page 248

Transistor functions as a switch. Explain.

Evaluation | Q III. 10. | Page 248

Describe the function of a transistor as an amplifier with the neat circuit diagram. Sketch the input and output wave forms.

Evaluation | Q III. 11. i) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of AND gate.

Evaluation | Q III. 11. ii) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of OR gate.

Evaluation | Q III. 11. iii) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of NOT gate.

Evaluation | Q III. 11. iv) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of NAND gate.

Evaluation | Q III. 11. v) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of NOR gate.

Evaluation | Q III. 11. vi) | Page 248

Give circuit symbol, logical operation, truth table, and Boolean expression of EX-OR gate.

Evaluation | Q II. 12. | Page 248

State and prove De Morgan’s first and second theorem.

Evaluation | Q III. 13. | Page 248

Explain the amplitude modulation with necessary diagrams.

Evaluation | Q III. 14. | Page 248

Explain the basic elements of the communication system with the necessary block diagram.

Evaluation | Q III. 15. | Page 248

Explain the ground wave propagation and space wave propagation of electromagnetic waves through space.

Evaluation | Q III. 16. | Page 248

Fiber optic communication is gaining popularity among the various transmission media. - justify

Evaluation | Q III. 17. | Page 248

List out the advantages and limitations of frequency modulation.

Evaluation | Q III. 18. | Page 248

What is meant by satellite communication?

Evaluation | Q III. 18. | Page 248

Give the applications of satellite communication.

Evaluation [Pages 248 - 250]

### Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide Chapter 10 Electronics and CommunicationEvaluation [Pages 248 - 250]

#### Numerical Problems

Evaluation | Q IV. 1. | Page 248

The given circuit has two ideal diodes connected as shown in the figure below. Calculate the current flowing through the resistance R1.

Evaluation | Q IV. 2. | Page 249

Four silicon diodes and a 10 Ω resistor are connected as shown in the figure below. Each diode has a resistance of 1 Ω. Find the current flows through the 10 Ω resistor.

Evaluation | Q IV. 3. | Page 249

Assuming VCEsat = 0.2 V and β = 50, find the minimum base current (IB) required to drive the transistor given in the figure to saturation.

Evaluation | Q IV. 4. | Page 249

A transistor of α = 0.99 and VBE = 0.7 V is connected in the common-emitter configuration as shown in the figure. If the transistor is in the saturation region, find the value of collector current.

Evaluation | Q IV. 5. | Page 249

In the circuit shown in the figure, the BJT has a current gain (β) of 50. For an emitter-base voltage VEB = 600 mV, calculate the emitter-collector voltage VEC (in volts).

Evaluation | Q IV. 6. | Page 250

Determine the current flowing through 3 Ω and 4 Ω resistors of the circuit given below. Assume that diodes D1 and D2 are ideal diodes.

Evaluation | Q IV. 7. i) | Page 250

Prove the following Boolean expression using the laws and theorems of Boolean algebra.

("A" + "B") ("A" + overline"B") = A

Evaluation | Q IV. 7. ii) | Page 250

Prove the following Boolean expression using the laws and theorems of Boolean algebra.

"A" (overline"A" + "B") = AB

Evaluation | Q IV. 7. iii) | Page 250

Prove the following Boolean expression using the laws and theorems of Boolean algebra.

(A + B) (A + C) = A + BC

Evaluation | Q IV. 8. | Page 250

Verify the given Boolean equation A + overline"A""B" = A + B using truth table.

Evaluation | Q IV. 9. | Page 250

In the given figure of a voltage regulator, a Zener diode of breakdown voltage 10 V is employed. Determine the current through the load resistance, the total current and the current through the diode. Use diode approximation.

Evaluation | Q IV. 10. | Page 250

Write down the Boolean equation for the output Y of the given circuit and give its truth table.

Evaluation

## Tamil Nadu Board Samacheer Kalvi solutions for Class 12th Physics Volume 1 and 2 Answers Guide chapter 10 - Electronics and Communication

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Concepts covered in Class 12th Physics Volume 1 and 2 Answers Guide chapter 10 Electronics and Communication are Introduction to Electronics, Diodes, Types of Semiconductors, Bipolar Junction Transistor (BJT), Digital Electronics, De Morgan’s Theorem, Boolean Algebra, Modulation, Introduction to Communication System, Antenna Size, The Elements of an Electronic Communication System, Propagation of Electromagnetic Waves, Satellite Communication, Radar and Applications, Fibre Optic Communication, Mobile Communication, Internet, Global Positioning System, Application of Information and Communication Technology in Agriculture, Fisheries and Mining.

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