Question 1

Which river is primarily allocated to Pakistan under the Indus Water Treaty?

Accepted Answer

The correct answer is: Indus. Under the Indus Waters Treaty of 1960, three western rivers—the Indus, Jhelum, and Chenab—were primarily allocated to Pakistan, while three eastern rivers—Ravi, Beas, and Sutlej—were allocated to India.

Question 2

Match the International newspaper to its base country:

1. The Guardian - i. China
2. The People's Daily - ii. Russia
3. El Pais - iii. United Kingdom
4. Kommersant - iv. Spain

Choose the correct option.

Accepted Answer

The correct answer is: 1-iii, 2-i, 3-iv, 4-ii. The correct matching is: The Guardian - United Kingdom (1-iii), The People's Daily - China (2-i), El Pais - Spain (3-iv), Kommersant - Russia (4-ii). This matches option A.

Question 3

In which year, Indus Water Treaty was signed?

Accepted Answer

The correct answer is: 1960. The Indus Waters Treaty was signed on September 19, 1960, in Karachi by Indian Prime Minister Jawaharlal Nehru and Pakistani President Ayub Khan.

Question 4

In television, 4: 3 represents the

Accepted Answer

The correct answer is: Aspect Ratio. The ratio of the width of a television screen to its height is called the aspect ratio. The traditional SDTV standard aspect ratio is 4:3.

Question 5

In T.V., the picture signal is

Accepted Answer

The correct answer is: Amplitude modulated and at the low-frequency end of each channel allocation. In television broadcasting, the video (picture) signal is amplitude modulated (using VSB) and its carrier is positioned at the lower/low-frequency end of the channel bandwidth allocation.

Question 6

A PAM signal can be demodulated using

Accepted Answer

The correct answer is: A Low pass filter. A Pulse Amplitude Modulated (PAM) signal contains the original message signal in its low-frequency envelope, which can be extracted by passing the PAM signal through a simple low pass filter.

Question 7

In time-division-multiplexing, each multiplexed signal occupies

Accepted Answer

The correct answer is: The Entire Transmission Bandwidth. In Time Division Multiplexing (TDM), different signals are allocated different time slots. During its allocated time slot, each signal occupies the entire transmission bandwidth.

Question 8

What will be the upper sideband and lower sideband frequencies for amplitude modulation of a 5-kHz signal with 40-KHz carrier frequency?

Accepted Answer

The correct answer is: 45 kHz and 35 kHz, respectively. Upper Sideband (USB) = fc + fm = 40 kHz + 5 kHz = 45 kHz. Lower Sideband (LSB) = fc - fm = 40 kHz - 5 kHz = 35 kHz.

Question 9

In FM to AM conversion, the input of the frequency-modulated signal converted into amplitude modulated signal by

Accepted Answer

The correct answer is: Differentiator. An FM signal can be converted to an AM signal by passing it through a differentiator (or slope detector) whose frequency response changes frequency variations into amplitude variations.

Question 10

Pulse amplitude modulation is a process whereby

Accepted Answer

The correct answer is: The height of a pulse is made proportional to the sampled value. Pulse Amplitude Modulation (PAM) is a modulation process where the amplitude (height) of the carrier pulses is made proportional to the amplitude of the sampled message signal.

Question 11

The amplitude modulation signal without a carrier is known as

Accepted Answer

The correct answer is: DSB-SC. An amplitude modulated signal where the carrier is suppressed (removed) and both sidebands are transmitted is known as Double Sideband Suppressed Carrier (DSB-SC).

Question 12

Choose the incorrect statement about Switch Mode Power Supplies (SMPS):

Accepted Answer

The correct answer is: SMPS has low input ripple. SMPS systems operate by high-frequency switching, which inherently generates high input and output ripple/noise. Thus, the statement that 'SMPS has low input ripple' is incorrect.

Question 13

The magnetic field produced in the stator of a three phase induction motor travels at

Accepted Answer

The correct answer is: Synchronous speed. In a three-phase induction motor, the rotating magnetic field (RMF) generated in the stator travels at synchronous speed ($N_s = 120f/P$).

Question 14

Alternating Current (AC) cannot be measured by DC ammeter because

Accepted Answer

The correct answer is: Average value of complete cycle is zero. A DC ammeter measures the average value of the current. Since a complete cycle of alternating current has equal positive and negative halves, its average value over a complete cycle is zero, resulting in no deflection.

Question 15

What is a common use of a Band Pass Filter in Radio Wave Propagation?

Accepted Answer

The correct answer is: It allows only a specific range of frequencies to pass through. A Band Pass Filter is designed to allow signals within a specific range of frequencies (passband) to pass while attenuating/blocking frequencies outside this range.

Question 16

Which of the permanent wiring systems is/are most preferably used for residential and commercial applications?

I. CTS
II. TRS
III. Cleat
IV. Conduit

Choose the correct answer.

Accepted Answer

The correct answer is: I, II and IV. Conduit wiring (IV) is the most preferred modern permanent system, but CTS (Cab Tyre Sheathed, I) and TRS (Tough Rubber Sheathed, II) are also classified as historical permanent wiring systems. Cleat wiring (III) is purely temporary. Thus, Option C is correct.

Question 17

The minimum clearance of the High Voltage (HV) line from the ground across the road should be

Accepted Answer

The correct answer is: 6.1 m. According to Indian Electricity Rules, the minimum ground clearance for high-voltage (HV) transmission lines (up to 11 kV) crossing across a street or road is 6.1 meters (20 feet).

Question 18

At start, the following information is correct for an induction motor:

I. Speed = 0
II. Slip = 0.5
III. Slip = 1
IV. Slip = 0

Choose the correct answer:

Accepted Answer

The correct answer is: I and III. At start, the motor is stationary, so speed N = 0 (I). The slip s is defined as $(N_s - N)/N_s$. Since N = 0, slip s = 1 (III). Thus, I and III are correct.

Question 19

Consider the following statements:

Statement (I): In AM systems the modulation index (0 < m < 1) should be high.
Statement (II): The higher the value of m, the greater the power in the sidebands.

Choose the correct option.

Accepted Answer

The correct answer is: Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I).. In AM systems, the sideband power is given by $P_c(m^2/2)$. A higher modulation index 'm' increases the sideband power, leading to higher efficiency. Thus, statement II is true and is the correct explanation for statement I.

Question 20

Which of the following is NOT a method for generating FM?

Accepted Answer

The correct answer is: By switching modulator. Reactance modulators, varactor diodes, and Armstrong modulators are standard methods used to generate FM signals. A switching modulator is used for generating AM (amplitude modulation) signals.

Question 21

RF carrier 15 kV at 1 MHz is amplitude modulated and modulation index is 0.8. Find the peak voltage of the signal.

Accepted Answer

The correct answer is: 12 kV. The peak voltage of the modulating signal alone is $V_m = m 	imes V_c = 0.8 	imes 15	ext{ kV} = 12	ext{ kV}$ (Option B). Mathematically, the peak voltage of the combined modulated signal is $15 	imes (1 + 0.8) = 27	ext{ kV}$, which is not in the choices, making 12 kV the intended correct option.

Question 22

In TV transmission, the picture signal is amplitude-modulated and the sound signal is frequency-modulated. This is done because

Accepted Answer

The correct answer is: bandwidth requirement is minimized. The bandwidth of a video signal is very high. Using AM (with VSB) for the video signal minimizes the transmission bandwidth requirement compared to wideband FM.

Question 23

The colour TV picture signal is a

Accepted Answer

The correct answer is: three-channel, three - dimensional signal. A color TV picture signal has three channels (such as R, G, B or Y, I, Q) representing three separate components, and it is three-dimensional (spatial coordinates x, y and time t).

Question 24

Which of the following statements is correct regarding induction motor?

Accepted Answer

The correct answer is: 1-phase induction motors produce low starting torque, whereas 3-phase induction motors produce high starting torque. Single-phase induction motors are not self-starting and have low starting torque compared to three-phase induction motors, which produce high starting torque and are self-starting.

Question 25

For a dipole antenna

Accepted Answer

The correct answer is: the radiation intensity is maximum along the normal to the dipole axis. For a dipole antenna, the radiation pattern is a torus (donut) shape, with maximum radiation intensity normal (perpendicular) to the axis of the antenna.

Question 26

Match List-X (Medium type) with List-Y (Frequency range) and select the correct answer using the codes given below the lists:

List-X:
i. Open wire
ii. Twisted pair
iii. Coaxial cable

List-Y:
1. 100 KHz
2. 100 MHz
3. 5 KHz

Accepted Answer

The correct answer is: 3, 1, 2. The correct matching is: Open wire has a bandwidth of about 5 kHz (i-3); Twisted pair has about 100 kHz (ii-1); Coaxial cable supports up to 100 MHz or more (iii-2). This matches option B.

Question 27

Fill in the blank. "The generation of single sideband suppressed carrier (SSB-SC) signal is done by ________ discrimination methods."

Accepted Answer

The correct answer is: Both A and B. SSB-SC signals are commonly generated using either the frequency discrimination (filter) method or the phase discrimination (phase-shift) method.

Question 28

Which of the following best describes interlaced scanning in a picture tube?

Accepted Answer

The correct answer is: Scanning odd lines first and then even lines in two passes. Interlaced scanning divides a video frame into two fields: the first field scans only the odd-numbered lines, and the second field scans only the even-numbered lines.

Question 29

Match the following terms with their correct descriptions and select the correct answer using the codes given below the lists.

List-X:
i. Progressive scanning
ii. SSB
iii. UHF
iv. Negative picture pulses

List-Y:
1. Transmits only one sideband of the signal
2. Scans each line in sequence
3. Frequency ranges from 300 MHz to 3 GHz
4. Pulses represent darker areas with higher voltage

Accepted Answer

The correct answer is: 2, 1, 3, 4. The correct matching is: Progressive scanning scans each line in sequence (i-2); SSB transmits only one sideband (ii-1); UHF frequency range is 300 MHz to 3 GHz (iii-3); Negative picture pulses have higher voltage for darker areas (iv-4). This matches option C.

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