Legal Metrology • Paper-III
A waveguide section in a microwave circuit acts as
A)
LP filter
B)
HP filter
C)
Band pass filter
D)
Band stop filter
Correct option: B — HP filter. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
A cavity resonator can be represented by
A)
An LC circuit
B)
An LCR circuit
C)
A lossy inductor
D)
A lossy capacitor
A cavity resonator is commonly represented by an equivalent lumped LC resonant circuit.
Legal Metrology • Paper-III
Free space wavelength is
A)
Greater than guided wavelength
B)
Equal to guided wavelength
C)
Lesser than guided wavelength
D)
None of the above
Guided wavelength is shorter than free-space wavelength because the guided wave has a lower phase velocity.
Legal Metrology • Paper-III
In microwave system the function of mode filter is
A)
to change mode of wave transmission
B)
to suppress modes with lower cut off frequencies
C)
to suppress modes with higher cut off frequencies
D)
both (a) & (c)
Correct option: D — both (a) & (c). This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
In high speed TDM, the channels are separated in the receiver employing
A)
OR gate
B)
NAND gate
C)
NOR gate
D)
AND gate
TDM is naturally used to multiplex digital streams into time slots.
Legal Metrology • Paper-III
What is the assigned bandwidth of each of the channels in the AM broadcast band?
A)
5 kHz
B)
15 kHz
C)
10 kHz
D)
200 kHz
A 7-bit PCM stream at 10 kHz has 70 kb/s bit rate; the corresponding baseband bandwidth is about 35 kHz for ideal Nyquist signaling.
Legal Metrology • Paper-III
The dominant mode in a rectangular waveguide is TE10 because this mode has
A)
No attenuation
B)
No cut-off
C)
No magnetic field component
D)
The highest cut-off wavelength
A single-conductor hollow rectangular waveguide cannot support a TEM mode.
Legal Metrology • Paper-III
A group of 8 bits:
A)
Digits
B)
Nibble
C)
Byte
D)
Word
Correct option: C — Byte. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
A microprocessor has 24 address lines and 32 data lines. If it uses 10 bits of opcode, the size of its Memory Buffer Register is
A)
22 bits
B)
24 bits
C)
32 bits
D)
14 bits
Correct option: C — 32 bits. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
The standard voice frequency band is
A)
300 Hz- 3400 Hz
B)
3 KHz-30 KHz
C)
20Hz-20 KHz
D)
30 Hz-3000Hz
The standard telephone voice band is approximately 300–3400 Hz.
Legal Metrology • Paper-III
The cycle required to fetch and execute an instruction in 8085 microprocessors is which one of the following?
A)
Memory cycle
B)
Clock cycle
C)
Instruction cycle
D)
Machine cycle
TRAP is the highest-priority 8085 interrupt.
Legal Metrology • Paper-III
High frequency waves follow
A)
The ground wave propagation
B)
The line of sight direction
C)
The bend along the curvature of earth
D)
The ionosphere propagation
Correct option: B — The line of sight direction. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
Computer address bus is
A)
Bidirectional
B)
Unidirectional
C)
Multidirectional
D)
Circular
Correct option: B — Unidirectional. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
One of the following communication system is analog
A)
PCM
B)
Delta
C)
Differential PCM
D)
PAM
Correct option: D — PAM. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
In a microwave test bench, the microwave signal is amplitude modulated at 1 kHz because
A)
To increase the sensitivity of the measurement
B)
To transmit the signal to a far-off place
C)
To study amplitude modulation
D)
As crystal detector fails at microwave frequencies
A low-frequency amplitude modulation is used so the detector output can be measured conveniently.
Legal Metrology • Paper-III
Which of the following is not a common microwave application?
A)
Telephone
B)
Mobile radio
C)
Radar
D)
Satellite communication
Correct option: A — Telephone. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
In commercial TV transmission in India, video and voice signals are modulated respectively as,
A)
VSB and VSB
B)
VSB and SSB
C)
VSB and FM
D)
FM and VSB
In India, vision uses vestigial-sideband AM and sound uses FM.
Legal Metrology • Paper-III
Digital modulation techniques are used in satellite communication system, because
A)
They are easy to handle
B)
Large bandwidth utilization is possible
C)
They have a spectral efficiency
D)
They are less prone to interference
Correct option: C — They have a spectral efficiency. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
Measurement of VSWR gives the degree of mismatch between the load and the
A)
Microwave components
B)
Transmission line
C)
Tubes
D)
Waveguides
Correct option: B — Transmission line. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
A fibre optic cable has the indices of refraction of core of 1.6 and of cladding of 1.4. For an angle of incidence 70°, the angle of return light ray will be
A)
35°
B)
61°
C)
70°
D)
90°
Correct option: B — 61°. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
The semiconductor diode which can be used in switching circuit in microwave range is
A)
Gunn diode
B)
Varactor diode
C)
PIN diode
D)
Tunnel diode
A high resistance is connected in series to limit the current through the voltmeter movement.
Legal Metrology • Paper-III
In 8085 which addressing mode is also called inherent addressing?
A)
Immediate
B)
Direct
C)
Register
D)
Implicit
TRAP is the highest-priority 8085 interrupt.
Legal Metrology • Paper-III
Typical power gain of TWT amplifier is
A)
1 to 5 dB
B)
50 to 300 dB
C)
100 to 400 dB
D)
20 to 40 dB
Correct option: D — 20 to 40 dB. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-III
For QPSK
A)
Error rate is lower than 16 MPSK
B)
Error rate is higher than QASK
C)
Signals are in time Quadrature
D)
More-inter symbols interference compared to MSK
ASK/PSK/FSK/QAM are digital-to-analog modulation methods because digital data alters an analog carrier.
Legal Metrology • Paper-III
The Klystron tube operates on which principle?
A)
Velocity modulation
B)
Current density modulation
C)
Amplitude modulation
D)
Frequency modulation
Correct option: A — Velocity modulation. This matches the standard definition/result for the stated question.
