Karnataka 2nd PUC Question Paper 2025 Electronics

Government of Karnataka
Karnataka Secondary Education Examination Board

Question Papers

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Registration No. :

X1 – 2025
«µÀAiÀÄ ¸ÀAPÉÃvÀ /
40 (NS)
Subject Code

J¯ÉPÁÖç¤Pïì («zÀÄå£Áä£À «eÕÁ£À) / ELECTRONICS
[¸ÀªÀÄAiÀÄ: 3 UÀAmÉUÀ¼ÀÄ] [MlÄÖ ¥Àæ±ÉßUÀ¼À ¸ÀASÉå : 45] [UÀjµÀ× CAPÀUÀ¼ÀÄ : 70]
[Time : 3 Hours] [Total No. of questions : 45] [Max. Marks : 70]

Instructions : 1) For Part – A questions, only the first written answer will be
considered for evaluation.
2) Part – D consists of two sections. Section – I is of essay
type questions and Section – II is of problems.
3) Circuit diagram and truth tables must be drawn wherever
necessary.
4) Solve the problems with necessary formulae.
5) For the questions having diagrams, alternate questions are
given at the end of the question paper in separate section
for visually challenged students.

PART – A

I. Select the correct answer from the choices given : (15 × 1 = 15)

1) An example for the voltage controlled device is
a) BJT b) FET
c) SCR d) TRIAC

P.T.O.

40 (NS) -2-

2) The operating point is also called as
a) Quiescent point b) Cutoff point
c) Saturation point d) Breakdown point

3) Conduction angle for class-B power amplifier is
a) 60° b) 180°
c) 270° d) 360°

4) What happens to voltage gain of an amplifier, when negative feedback is
applied?
a) Increases b) Decreases
c) Remains same d) Oscillates

5) The rate of change of output voltage in op-amp is known as
a) Input offset voltage b) CMRR
c) Output offset voltage d) Slew rate

6) The active component used in op-amp filter circuit is
a) Resistor b) Op-amp
c) Capacitor d) Inductor

7) Name the high frequency stability oscillator
a) Colpitts oscillator b) Hartley oscillator
c) Wein bridge oscillator d) Crystal oscillator

8) The layer of ionosphere which remains during both day and night time is
a) F Layer b) E Layer
c) D Layer d) Troposphere

-3- 40 (NS)

9) The intermediate frequency in AM radio receiver is
a) 455 Hz b) 455 KHz
c) 455 MHz d) 455 GHz

10) The common name of SCR is
a) Diode b) TRIAC
c) MOSFET d) Thyristor

11) 8421 BCD code for (59)10 is
a) 0101 1010 b) 0110 1001
c) 0101 1001 d) 1001 0101

12) In a flip-flop, SET condition stands for
a) Q = 0, Q = 0 b) Q = 0, Q = 1
c) Q = 1, Q = 0 d) Q = 1, Q = 1

13) How many timers are present in 8051 microcontroller?
a) 1 b) 2
c) 3 d) 4

14) ‘Not equal to’ operator in C programming is
a) ~ b) ≠
c) =! d) !=

15) Expansion of CDMA is
a) Code Division Mobile Access
b) Call Division Mobile Access
c) Code Division Multiple Access
d) Call Division Multiple Access

40 (NS) -4-

II. Fill in the blanks by choosing appropriate answer from the bracket : (5 × 1 = 5)

[ a) combinational b) damped c) twice d) comparator e) thermal f) highest ]

16) CE amplifier has _____________ power gain.

17) Zero crossing detector is an application of _____________.

18) Tank circuit produces _____________ oscillations.

19) Carrier swing is _____________ the frequency deviation in FM.

20) Half adder is a _____________ circuit.

PART – B

III. Answer any five questions : (5 × 2 = 10)

21) Mention any two types of transistor biasing circuits.

22) In an amplifier bandwidth is 1 MHz and β = 0.01. Determine bandwidth
when negative feedback is introduced. Given A = 100.

23) A transistor colpitts oscillator is provided with L = 10 μ H and C eq = 1nF .
Determine frequency of oscillations.

24) Write the expression for PT in terms of PC . What is the upper limit of ma
in AM?

25) Name the four types of power converters.

26) Draw the logic circuit of a full adder using 3 - input X-OR gate and basic
gates.

27) Distinguish between ROM and RAM.

28) Write a note on Wifi.

-5- 40 (NS)

PART – C
IV. Answer any five questions : (5 × 3 = 15)

29) Mention the differences between FET and BJT.

30) Derive an expression for input impedance of voltage series negative
feedback amplifier.

31) Sketch nature of oscillator output waveform for a) Aβ > 1 b) Aβ < 1
c) Aβ = 1

32) What is noise signal? Differentiate between radio horizon and optical
horizon.

33) Draw the circuit diagram of diode detector. Sketch the waveforms at
different stages.

34) Determine Vdc and Idc of SCR HWR. Given firing angle is 60°, rms
voltage to the rectifier is 230 V and a load of 20 Ω is connected.

35) Convert (1010)2 into gray code using X-OR gate.

36) Write any three uses of fiber optic communication.

PART – D (Section I)
V. Answer any three questions : (3 × 5 = 15)
37) Explain working of CC amplifier. Draw input and output waveforms.
38) Derive an expression for the output voltage of an op-amp summing
amplifier.
39) Realize NOT, AND, OR and XOR gates using NAND gates.
40) Write ALP program to divide 3 FH by 2 AH. In which registers, quotient
and remainder are stored after execution of the program.
41) Write a C program to accept two integer number and print whether they
are equal or not equal.

40 (NS) -6-

PART – D (Section II)

VI. Answer any two questions : (2 × 5 = 10)

42) For the given CE amplifier circuit using silicon transistor.
Calculate

(i) V2 (Voltage drop across R 2 )

(ii) IE

(iii) re′

(iv) AV

(v) Ai

26 mV
Given re′ = , VBE = 0.7 V and β = 150 .
IE

-7- 40 (NS)

43) Calculate output voltages for the op-amp circuits shown below. Given
Vi 1 = 1 V , Vi 2 = 2 V . (2 + 3)

a)

b)

40 (NS) -8-

44) A sinusoidal carrier voltage v c = 60 sin 2π × 10 5 t is modulated by a
sinusoidal voltage v m = 30 sin 2π × 10 3 t .

(a) Draw the frequency spectrum of AM

(b) Calculate bandwidth.

45) Simplify the Boolean expression
Y(A, B, C, D) =  m(1, 4, 5, 11, 14) +  d(0, 10, 15)
Draw the NAND gate equivalent circuit to realize the simplified equation.

PART – E

(For Visually Challenged Students Only)

42) For the CE amplifier circuit using silicon transistor R1 = 45 kΩ , R 2 = 5 kΩ ,
26 mV
R C = 2 kΩ , R E = 470 Ω , VCC = +15 V , β = 150 , VBE = 0.7 V , re′ =
IE

Calculate
(i) V2 (Voltage drop across R 2 )

(ii) IE

(iii) re′

(iv) A V

(v) Ai (5)

43) a) An op-amp inverting amplifier is provided with R i 1 = 4.7 kΩ ,
R f 1 = 10 kΩ , V1 = 1 V . Determine output voltage V01 . (2)

b) An op-amp non-inverting amplifier is provided with R i 2 = 8.2 kΩ ,
R f 2 = 20 kΩ , V2 = 2 V . Determine output voltage V02 . (3)

—————

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