Kerala Plus Two Question Paper 2025 Electronics

KERALA BOARD

QUESTION
PAPER
2025
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Kerala Board of Public
Examinations

SY-431
Reg. No. : ......................................

Name : ...........................................

SECOND YEAR HIGHER SECONDARY EXAMINATION, MARCH 2025

Part – III Time : 2 Hours
ELECTRONICS Cool-off time : 15 Minutes
Maximum : 60 Scores

General Instructions to Candidates :
 There is a ‘Cool-off time’ of 15 minutes in addition to the writing time.
 Use the ‘Cool-off time’ to get familiar with questions and to plan your answers.
 Read questions carefully before answering.
 Read the instructions carefully.
 Calculations, figures and graphs should be shown in the answer sheet itself.
 Malayalam version of the questions is also provided.
 Give equations wherever necessary.
 Electronic devices except non-programmable calculators are not allowed in the
Examination Hall.

 
    15  ‘  ’ .
 ‘  ’    
 .
      .
    .
  , , ,   
.
   .
    .
     
    .

SY-431 1 P.T.O.

Answer all questions from 1 to 9. Each carries 1 score. (9  1 = 9)
1. Which circuit is known as amplitude limiter ?
(Clipper, Clamper, Integrator, Differentiator)

2. What will be the output of S-R Flip Flop using NOR Gate when the inputs are S = 1
R=1?
(Qn, 1, 0, Invalid)

3. In frequency modulation, which character of the carrier is varied in accordance with the
amplitude of the message signal ?
(Phase, Frequency, Amplitude, Voltage)

4. The unit of frequency is _____ .

5. Pick any one light source which is used in optical fiber communication.
(LED, Photo diode, Pin diode, Photo transistor)

6. The total channel bandwidth of Indian TV transmission is _____ .
(5 MHz, 6 MHz, 7 MHz, 8 MHz)

7. The sequence of instructions written in binary numbers are known as _____ .
(Assembly language, Machine language, High level language, 4th generation
language)

8. World wide network of computers is called _____ .
(LAN, MAN, WAN, Internet)

9. In cell phone system, the cell with 1 km diameter is called _____ cell.
(Micro Cell, Macro Cell, Pico Cell, Cluster)

SY-431 2

1  9    . 1  .

(9  1 = 9)
1.        ?
(, , , )

2. S=1 R = 1   NOR    S-R  
  ?
(Qn, 1, 0, )

3.     
     ?
(, , , )

4.   _____ .

5.      
 .
(LED,  ,  ,  )

6.  TV      _____ .
(5 MHz, 6 MHz, 7 MHz, 8 MHz)

7.       _____
.
( ,  ,   , 4-  )

8.    _____  .
(LAN, MAN, WAN, )

9.    1    _____ 
.
( ,  ,  ,  )

SY-431 3 P.T.O.

Answer any 7 questions from 10 to 19. Each carries 2 scores. (7  2 = 14)
10. Draw the block diagram of a regulated power supply.

11. Draw the circuit diagram of a negative clamper.

12. (a) How many select lines required for a 4:1 multiplexer ? (1)
(b) Draw the symbol of 4:1 multiplexer. (1)

13. Draw the frequency spectrum of AM wave.

14. What do you mean by skip distance in connection with skywave propogation ?

15. State and explain sampling theorem.

16. Draw the structure of optical fiber.

17. Classify the following devices into input and output units.
(Mouse, Scanner, Printer, Speaker)

18. Write any two advantages of computer networking.

19. Draw the structure of cluster in cell phone system.

Answer any 7 questions from 20 to 28. Each carries 3 scores. (7  3 = 21)
20. Draw the circuit diagram of a shunt voltage regulator using Zener diode.

21. (a) Draw the circuit diagram of low pass filter. (2)
(b) Draw the frequency response of low pass filter. (1)

SY-431 4

10  19    7  .
2  . (7  2 = 14)
10.      .

11.     .

12. (a)  4:1      ? (1)
(b) 4:1   . (1)

13. AM    .

14.        
   ?

15.    .

16.    .

17.       .
(, , , )

18.    2  .

19.      .

20  28    7  .
3  . (7  3 = 21)
20.       
 .

21. (a)      . (2)
(b)       . (1)

SY-431 5 P.T.O.

22. Draw the logic circuit diagram of J-K Flip-Flop.

23. Write any 3 points on need for modulation.

24. Explain the digital modulation technique ASK – Amplitude shift keying with relevant
figure.

25. What you mean by Dispersion in optical fiber ? Explain with necessary figures.

26. Write a short note on interlaced scanning in television.

27. Draw the basic block diagram of a computer.

28. What are the difference between LAN, MAN and WAN ?

Answer any 4 questions from 29 to 33. Each carries 4 scores. (4  4 = 16)
29. (a) Draw the connection diagram of 3 pin IC voltage regulator. (2)
(b) Explain the need for capacitors that are connected in the input and output of the
above circuit. (2)

30. (a) Draw the circuit diagram of a summing amplifier. (3)
(b) Write the equation for the output of summing amplifier. (1)

31. Draw the block diagram of superheterodyne receiver.

32. (a) Draw the block diagram of optical fiber communication system. (3)
(b) Write any two advantages of optical fiber communication system. (1)

33. Draw the block diagram of monochrome TV receiver.
____________

SY-431 6

22. J-K     .

23.     3  .

24.    ASK –    
   .

25.      ? 
  .

26.        
 .

27.     .

28. LAN, MAN, WAN     ?

29  33    4  .
4  . (4  4 = 16)
29. (a) 3   IC     . (2)
(b)     
   . (2)

30. (a)      . (3)
(b)     . (1)

31.      .

32. (a)      
. (3)
(b)     
2  . (1)

33.  TV    .

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SY-431 7 P.T.O.

SY-431 8