Kerala Plus One Question Paper 2025 Electronics

KERALA BOARD

QUESTION
PAPER
2025
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Kerala Board of Public
Examinations

FY-331
Reg. No. : ......................................

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

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

FY-331 1 P.T.O.

Answer all questions from 1 to 9. Each carries 1 score. (9  1 = 9)

1. The value of resistor with the colour code Brown, Black and Red is __________.

(a) 100  (b) 1 k

(c) 10 k (d) 100 k

2. The electric power P = __________.

(a) V·R (b) I·R

(c) V·I (d) V·I·R

3. The range of energies possessed by conducting electrons is known as __________.

(a) Valence band (b) Conduction band

(c) Forbidden energy gap (d) None of these

4. Draw the symbol of a diode.

5. The emitter current of NPN transistor, IE = ________.

(a) IB – IC (b) IC – IB

(c) IB + IC (d) None of these

6. The Peak Inverse Voltage (PIV) of half wave rectifier is ________.

(a) Vm (b) 2 Vm

(c) 3 Vm (d) 4 Vm

FY-331 2

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

(9  1 = 9)

1. , ,      __________
.

(a) 100  (b) 1 k
(c) 10 k (d) 100 k

2.   P = __________.

(a) V·R (b) I·R

(c) V·I (d) V·I·R

3.       
__________ .

(a)   (b)  
(c)    (d) 

4.    .

5.  NPN    IE = ________.

(a) IB – IC (b) IC – IB

(c) IB + IC (d) 

6.    ,    ________ .
(a) Vm (b) 2 Vm

(c) 3 Vm (d) 4 Vm

FY-331 3 P.T.O.

7. Which one of the below oscillator has the most stable frequency ?

(a) RC oscillator (b) LC oscillator

(c) Crystal oscillator (d) Phase shift oscillator

8. In a Binary Number System, a number is represented by ____________.

(a) 0 and 1 (b) 1 and 2

(c) 2 and 3 (d) 0 and 2

9. A galvanometer can be converted to voltmeter by connecting _________ in series with
it.

(a) low value resistor (b) high value resistor

(c) low value capacitor (d) high value capacitor

Answer any 7 questions from 10 to 19. Each carries 2 scores. (7  2 = 14)

10. Write any two applications of electronics in medical field.

11. State Ohm’s law.

12. Explain the below terms related to charge carrier transportation in semiconductors
shortly :

(i) Diffusion (1)

(ii) Drift (1)

13. Draw the V-I characteristics of an ideal diode.

FY-331 4

7.       
 .
(a) RC  (b) LC 

(c)   (d)   

8.        ____________
.
(a) 0  1  (b) 1  2 

(c) 2  3  (d) 0  2 

9.    _________  
 
(a)    (b)   
(c)    (d)   

10  19    7  .
2  . (7  2 = 14)

10.      
.

11.   .

12.     
   .
(i)  (1)

(ii)  (1)

13.      (V-I)  
.
FY-331 5 P.T.O.

14. Draw the symbol of the below :

(i) NPN transistor (1)

(ii) PNP transistor (1)

15. The below words stand for :

(i) JFET (1)

(ii) MOSFET (1)

16. Draw the circuit diagram of a half-wave rectifier.

17. What are the two disadvantages (drawbacks) of fixed bias of a transistor amplifier ?

18. Explain shortly, the below terms related to an oscillator :

(i) Damped oscillator (1)

(ii) Undamped oscillator (1)

19. Digital signals have only two states, that are __________ and __________.

Answer any 7 questions from 20 to 28. Each carries 3 scores. (7  3 = 21)

20. Draw the symbol of Air core, Iron core and Ferrite Core Inductors.

21. Explain the below terms related to sine wave :

(a) Frequency (1)

(b) Time period (1)

(c) Phase angle (1)

FY-331 6

14.     :
(i) NPN  (1)
(ii) PNP  (1)

15.      :
(i) JFET (1)
(ii) MOSFET (1)

16.       .

17.      
 .

18.     
.
(i)   (1)
(ii)   (1)

19.      _________  __________  .

20  28    7  .
3  . (7  3 = 21)
20. , ,    
.

21.        :
(a)  () (1)
(b)   (1)

(c)   (1)

FY-331 7 P.T.O.

22. Draw the energy band diagrams of the following :

(a) Insulator (1)

(b) Semi-conductor (1)

(c) Conductor (1)

23. (i) Draw the symbol of a Zener diode. (1)

(ii) Compare avalanche breakdown and Zener breakdown occur in a P-N junction
diode. When reverse biased, voltage is increased. (2)

24. Fill in the blanks of the following table :

E-B Junction C-B Junction Mode of Operation

(a) Forward Reverse __________ (1)

(b) Forward ____________ Saturation (1)

(c) ____________ Reverse Cut-off (1)

25. Explain the below terms related to JFET :

(a) Source (1)

(b) Drain (1)

(c) Gate (1)

26. Draw the circuit diagram and input output waveforms of Bridge Rectifier.

27. Draw the block diagram of a Public Address System (PA System).

FY-331 8

22.     .
(a)  (1)

(b)   (1)

(c)  (1)

23. (i)     . (1)

(ii)      P-N  
   ,    
  . (2)

24.     :

E-B  C-B    

(a)   __________ (1)

(b)  ____________  (1)

(c) ____________  - (1)

25.  JFET      :
(a)  (1)

(b)  (1)

(c)  (1)

26.      , 
 .

27.     ( )   .
(.. )

FY-331 9 P.T.O.

28. Convert the below binary numbers to its equivalent decimal number :

(i) (10110)2

(ii) (111101)2

(iii) (1111)2

Answer any 4 questions from 29 to 33. Each carries 4 scores. (4  4 = 16)

29. (i) In Common Emitter Configuration (CE) of NPN transistor, the current
amplification factor or current gain  = ____________. (1)

(ii) Derive an expression for the relationship between  and . (3)

30. (i) The ripple factor of half wave rectifier is ___________. (1)

(ii) The ripple factor of full wave rectifier is ___________. (1)

(iii) The efficiency of half wave rectifier is ___________. (1)

(iv) The efficiency of full wave rectifier is ___________. (1)

31. (i) Draw the circuit diagram of voltage divider biasing amplifier circuit using a NPN
transistor. (2)

(ii) Derive an expression for IC and VCE of the above amplifier. (2)

32. What is the role of tank circuit in an oscillator ? Explain with necessary diagrams.

33. Draw the Logic Symbol, Output equation and Truth table of NAND gate.

____________

FY-331 10

28.      
   :
(i) (10110)2
(ii) (111101)2
(iii) (1111)2

29  33    4  .
4  . (4  4 = 16)
29. (i)  NPN    (CE) 
       = ________
. (1)
(ii)     (  )    
 . (3)

30. (i)   ,   ___________ . (1)
(ii)      ___________ . (1)
(iii)     ___________ . (1)
(iv)     ___________ . (1)

31. (i)  NPN  ,   
   . (2)
(ii)    IC  VCE   
 . (2)

32.       
 .

33.  NAND      , 
.
____________

FY-331 11 P.T.O.

FY-331 12