Jkp Constable Telecommunication Telecommunication Mcqs Jkp Constable (1089 MCQs)

Question 81 Discuss

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What is the standard Form Factor value for a pure sinusoidal alternating current?

A

1.0

B

1.11

C

1.414

D

1.732

Answer & Explanation

Correct Option: B

Form Factor is RMS value / Average value. For a sine wave, it is (Vm/sqrt(2)) / (2Vm/pi) = pi / (2 * sqrt(2)) = 1.11.

Question 82 Discuss

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Eddy current losses in a transformer core can be primarily reduced by:

A

Using a solid steel core

B

Increasing the frequency of supply

C

Laminating the core

D

Using thicker wire for the windings

Answer & Explanation

Correct Option: C

Laminating the core inserts thin insulating layers, breaking the path of eddy currents and greatly reducing the I^2R heating losses.

Question 83 Discuss

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According to Indian electrical wiring standards (IS), what is the standard color code for the Earth wire?

A

Red

B

Black

C

Green

D

Yellow

Answer & Explanation

Correct Option: C

In domestic wiring standard color coding, Red/Brown is phase, Black/Blue is neutral, and Green or Green-Yellow is earth.

Question 84 Discuss

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Which type of DC generator is typically used as an exciter to supply field current for a large alternator?

A

DC Series Generator

B

DC Shunt Generator

C

Differentially Compounded Generator

D

Arc Welding Generator

Answer & Explanation

Correct Option: B

DC Shunt generators provide a nearly constant output voltage over a wide load range, making them ideal as exciters.

Question 85 Discuss

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The tendency of a squirrel cage induction motor to run at a stable speed of one-seventh of its synchronous speed is known as:

A

Cogging

B

Crawling

C

Plugging

D

Hunting

Answer & Explanation

Correct Option: B

Crawling is caused by the 7th space harmonic of the air gap flux, creating a parasitic torque that peaks near 1/7th synchronous speed.

Question 86 Discuss

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In Delta Modulation, 'slope overload' distortion occurs when:

A

The signal frequency is too low

B

The step size is too large for a slowly varying signal

C

The analog signal varies faster than the modulator can track

D

The sampling rate exceeds the Nyquist criterion

Answer & Explanation

Correct Option: C

Slope overload happens when the rate of rise or fall of the analog input exceeds the maximum step size variation possible in Delta Modulation.

Question 87 Discuss

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In the standard GSM 900 MHz band, what is the frequency separation (duplex gap) between the uplink and downlink carriers?

A

10 MHz

B

25 MHz

C

45 MHz

D

80 MHz

Answer & Explanation

Correct Option: C

GSM 900 uses 890-915 MHz for uplink and 935-960 MHz for downlink, leaving a consistent duplex gap of 45 MHz.

Question 88 Discuss

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Why is a PIN diode widely used as an RF or microwave switch?

A

It acts as a variable capacitor under forward bias

B

It has an extremely high reverse breakdown voltage

C

Its intrinsic layer acts like a pure resistor at high frequencies, controllable by DC bias

D

It provides high power gain like a transistor

Answer & Explanation

Correct Option: C

At RF, the PIN diode's intrinsic layer cannot respond to the fast AC cycles. It behaves as a low resistance when forward-biased (switch ON) and high resistance when reverse-biased (switch OFF).

Question 89 Discuss

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An isolator is used in microwave transmission lines to:

A

Amplify the forward signal

B

Allow signal transmission in one direction and absorb reflections

C

Split the signal equally into two paths

D

Change the plane of polarization

Answer & Explanation

Correct Option: B

Isolators utilize ferrite materials to permit microwave energy to pass forward with little loss while heavily attenuating reflected energy travelling backwards.

Question 90 Discuss

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Corona discharge in high voltage transmission lines leads to:

A

Decrease in line capacitance

B

Generation of ozone and radio interference

C

Improvement in voltage regulation

D

Reduction of the skin effect

Answer & Explanation

Correct Option: B

The ionization of air around the conductor produces a faint glow, hissing noise, ozone gas, and significant RF interference.

jkp constable telecommunication

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Practice Questions

What is the standard Form Factor value for a pure sinusoidal alternating current?

Answer & Explanation

Eddy current losses in a transformer core can be primarily reduced by:

Answer & Explanation

According to Indian electrical wiring standards (IS), what is the standard color code for the Earth wire?

Answer & Explanation

Which type of DC generator is typically used as an exciter to supply field current for a large alternator?

Answer & Explanation

The tendency of a squirrel cage induction motor to run at a stable speed of one-seventh of its synchronous speed is known as:

Answer & Explanation

In Delta Modulation, 'slope overload' distortion occurs when:

Answer & Explanation

In the standard GSM 900 MHz band, what is the frequency separation (duplex gap) between the uplink and downlink carriers?

Answer & Explanation

Why is a PIN diode widely used as an RF or microwave switch?

Answer & Explanation

An isolator is used in microwave transmission lines to:

Answer & Explanation

Corona discharge in high voltage transmission lines leads to:

Answer & Explanation

jkp constable telecommunication

Topics

Browse Topics

Practice Questions

What is the standard Form Factor value for a pure sinusoidal alternating current?

Answer & Explanation

Eddy current losses in a transformer core can be primarily reduced by:

Answer & Explanation

According to Indian electrical wiring standards (IS), what is the standard color code for the Earth wire?

Answer & Explanation

Which type of DC generator is typically used as an exciter to supply field current for a large alternator?

Answer & Explanation

The tendency of a squirrel cage induction motor to run at a stable speed of one-seventh of its synchronous speed is known as:

Answer & Explanation

In Delta Modulation, 'slope overload' distortion occurs when:

Answer & Explanation

In the standard GSM 900 MHz band, what is the frequency separation (duplex gap) between the uplink and downlink carriers?

Answer & Explanation

Why is a PIN diode widely used as an RF or microwave switch?

Answer & Explanation

An isolator is used in microwave transmission lines to:

Answer & Explanation

Corona discharge in high voltage transmission lines leads to:

Answer & Explanation

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