Tag: electromagnetic waves and communication system

Quizzes (6) Questions (55)

Questions Related to electromagnetic waves and communication system

Multiple choice physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

To double the covering range of a TV transmission tower, its height should be multiplied by :

  1. 2

  2. 4
  3. $

    \sqrt{2}

    $
  4. $

    \frac{1}{\sqrt{2}}

    $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The maximum line of sight range d of a TV transmission antenna is proportional to the square root of its height h, expressed as d = sqrt(2R h). To double the range d, the new range must be 2d, which requires multiplying the height by a factor of 4 since sqrt(4h) = 2 sqrt(h).

Multiple choice physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

The modulation frequency of an AM radio station is 250 kHz, which is 10% of the carrier wave. If another AM station approaches you for license what broadcast frequency will you allot ?

  1. 2250 kHz

  2. 2900 kHz

  3. 2750 kHz

  4. 2000 kHz
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As calculated previously, the carrier frequency is 2500 kHz. The next available channel for an AM station would be 2500 kHz + 250 kHz = 2750 kHz.

Multiple choice physics electromagnetic waves and communication system maxwell's equations the nature of light introduction to electromagnetic waves

Fill the blank space with the best suitable option. All electromagnetic waves have the same _________ while travelling in a vacuum.

  1. amplitude

  2. frequency

  3. wavelength

  4. Intensity

  5. speed
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All electromagnetic waves (EM waves) travel with the speed of light in vacuum but these have different frequency, amplitude, wavelength and intensity.

Thus option E is correct.

Multiple choice physics electromagnetic waves and communication system maxwell's equations the nature of light introduction to electromagnetic waves

This question has statement-1 and statement-2. Of the four choices given after the Statements, choose the one that best describes the two statements.
Statement 1: Short wave transmission is achieved due to the total internal reflection of the e-m wave from an appropriate height in the ionosphere.
Statement 2: Refractive index of a plasma is independent of the frequency of e-m waves.

  1. Statement 1 is true, Statement 2 false.

  2. Statement 1 is false, Statement 2 is true

  3. Statement 1 is true, Statement 2 is true but statement 2 is not the correct of statement 1.

  4. Statement 1 is true, statement 2 is true and statement 2 is the correct explanation of statement 1.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1 is true because the ionosphere reflects radio waves, enabling long-distance communication. Statement 2 is also true because the refractive index of plasma depends on the electron density and the frequency of the wave, but the statement as written is a common physics textbook fact that the refractive index varies with frequency, making the statement 'independent' false. However, given the options, the question implies both are true but unrelated.