Technical Officer, SCERT • 2025 • Paper-III
Distances near the skip distance should be used for sky-wave propagation to-
A)
avoid tilting
B)
prevent sky-wave and upper ray interference
C)
avoid the Faraday effect
D)
not exceed the critical frequency
Option B is correct: prevent sky-wave and upper ray interference.
Technical Officer, SCERT • 2025 • Paper-III
When a signal is reconstructed from sampled data, what is the process called?
A)
Quantization
B)
Filtering
C)
Interpolation
D)
Decoding
Option C is correct: Interpolation.
Technical Officer, SCERT • 2025 • Paper-III
Square Law modulators :
A)
used for amplitude modulation
B)
have non linear current-voltage characteristics
C)
have non linear current-voltage characteristics as well as used for Amplitude Modulation
D)
used for frequency modulation
Option C is correct: have non linear current-voltage characteristics as well as used for Amplitude Modulation.
Technical Officer, SCERT • 2025 • Paper-III
The Q-factor of a microwave resonator and an antenna should be respectively-
A)
high, high
B)
high, low
C)
low, high
D)
low, low
Option B is correct: high, low.
Technical Officer, SCERT • 2025 • Paper-III
Large microwave power can be measured with the help of-
A)
Bolometer
B)
Calorimeter
C)
Thermister
D)
Baretter
Option B is correct: Calorimeter.
Technical Officer, SCERT • 2025 • Paper-III
A 400W carrier wave is modulated to a depth of 65%. Find the total power of modulated wave?
A)
399W
B)
311.5W
C)
546.3W
D)
484.5W
Option D is correct: 484.5W.
Technical Officer, SCERT • 2025 • Paper-II
A bulb in a staircase has two switches, one switch being on the ground floor and the other one on the first floor. The bulb can be turned ON and can be turned OFF by any one of the switches irrespective of the state of the other switch. The logic of switching of the bulb resembles-
A)
an AND gate
B)
an OR gate
C)
an XOR gate
D)
a NAND gate
Option C is correct: an XOR gate.
Technical Officer, SCERT • 2025 • Paper-II
The dominant mode in a rectangular waveguide is-
A)
TM11
B)
TE10
C)
TE01
D)
TM01
Option B is correct: TE10.
Technical Officer, SCERT • 2025 • Paper-II
The average power density of an electromagnetic wave is
A)
>(ExH')
B)
>(éx)
C)
5(4 XH')
D)
5(4 XH)
Option A is correct: >(ExH').
Technical Officer, SCERT • 2025 • Paper-II
Out of the following, which one is a broadband antenna?
A)
Horn
B)
Parabolic Dish
C)
Yagi-Uda
D)
Log Periodic
Option D is correct: Log Periodic.
Technical Officer, SCERT • 2025 • Paper-II
An ideal OP-Amp is an ideal
A)
Voltage controlled voltage source
B)
Voltage controlled Current source
C)
Current controlled voltage source
D)
Current controlled current source
Option A is correct: Voltage controlled voltage source.
Technical Officer, SCERT • 2025 • Paper-II
Calculate the energy in an electric field with flux density 6 units and field intensity of 4 units.
A)
12 Units
B)
32 Units
C)
2 Units
D)
22 Units
Option A is correct: 12 Units.
Technical Officer, SCERT • 2025 • Paper-II
Nichol’s chart is useful for the detailed study of:
A)
Closed loop frequency response
B)
Open loop frequency response
C)
Close loop and open loop frequency responses
D)
None of the above
Option A is correct: Closed loop frequency response.
Technical Officer, SCERT • 2025 • Paper-II
Which of the following options is a Current-Mode logic used in Digital Circuits?
A)
RTL
B)
ECL
C)
TTL
D)
IC
Option B is correct: ECL.
Technical Officer, SCERT • 2025 • Paper-II
The piezoelectric effect in a crystal is
A)
A voltage developed because of mechanical stress
B)
A change in resistance because of temperature
C)
A change in frequency because of temperature
D)
None of the above
Option A is correct: A voltage developed because of mechanical stress.
Technical Officer, SCERT • 2025 • Paper-II
What is the true statement about magnetic potential (A) and electric potential (V)?
A)
Both A and V are scalar
B)
A is scalar and V is vector
C)
A is vector and V is scalar
D)
Both A and V are vector
Option A is correct: Both A and V are scalar.
Technical Officer, SCERT • 2025 • Paper-II
Given that CMRR is 120 dB, input common mode voltage is 16V, differential voltage gain is 3400, output common mode voltage is-
A)
212.5 mv
B)
243.4 mv
C)
66.3 mv
D)
54.4 mv
Option D is correct: 54.4 mv.
Technical Officer, SCERT • 2025 • Paper-II
What is the phase shift in RC coupled CE amplifier at lower 3 dB frequency?
A)
180°
B)
225°
C)
270°
D)
100°
Option A is correct: 180°.
Technical Officer, SCERT • 2025 • Paper-II
The largest two digit hexadecimal number is
A)
FF₁₆
B)
EE₁₆
C)
EF₁₆
D)
GE₁₆
Option A is correct: FF₁₆.
Technical Officer, SCERT • 2025 • Paper-II
The action of JFET in its equivalent circuit can best be represented as a-
A)
current controlled current source
B)
current controlled voltage source
C)
voltage controlled voltage source
D)
voltage controlled current source
Option D is correct: voltage controlled current source.
Technical Officer, SCERT • 2025 • Paper-II
Which of the following codes is a sequential code?
A)
8421 code
B)
2421 code
C)
4221 code
D)
3421 code
Option A is correct: 8421 code.
Technical Officer, SCERT • 2025 • Paper-II
If a closed loop control system operates at a point on jω axis, the system is-
A)
marginally stable
B)
overdamped
C)
underdamped
D)
stable
Option A is correct: marginally stable.
Technical Officer, SCERT • 2025 • Paper-II
The electrostatic energy in an electric field does not depend on which of the following?
A)
Magnitude of charges
B)
Permittivity
C)
Applied electric field
D)
Flux lines
Option D is correct: Flux lines.
Technical Officer, SCERT • 2025 • Paper-II
Simplified form of the Boolean expression F ( P,Q,R,S ) = PQ'R + PQS + P'RS + P'R'S is-
A)
PQ + QR
B)
PS + QR
C)
PQ + RS
D)
PS + QS
Option B is correct: PS + QR.
Technical Officer, SCERT • 2025 • Paper-II
A lossless transmission line carrying a wave of wavelength λ can be modelled as an inductor if its length (L) is-
A)
L > λ/4
B)
L = λ/2
C)
L < λ/4
D)
L = λ/4
Option C is correct: L < λ/4.
