We need modulation. Which of the following four alternatives is not correct?

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Important Questions on Communication System

EASY

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 23 - Communication System>EXERCISE 23>Q 2

If

E_{c} = 20 \sin 10^{5} π t

and

E_{m} = 10 \sin 400 π t

are carrier and modulating signals respectively, the modulation index is

MEDIUM

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 23 - Communication System>EXERCISE 23>Q 3

Carrier wave of frequency

1000 Hz

is amplitude modulated by the signal frequency

200 - 4000 Hz

. The width of the channel of the case is

EASY

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 23 - Communication System>EXERCISE 23>Q 4

A signal wave of

12 kHz

is modulated with a carrier wave of frequency

2.51 MHz

. The upper and lower side-band frequencies are respectively

MEDIUM

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 23 - Communication System>EXERCISE 23>Q 5

The question has statement I and statement II of the four choices given after the statements, choose the one that best describes the two statements. Statement I: These signals are in general, less stable than ground wave signals. Skywave signals are used for long-distance radio communication. Statement II: The state of ionosphere varies from hour to hour, day to day and season to season.

MEDIUM

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 23 - Communication System>EXERCISE 23>Q 6

Find the height of antenna in which the distance of coverage of a transmitting antenna is