Question

AM radio signals have frequencies between 550 kHz and 1600 kHz (kilohertz) and travel with a speed of 3.00 108 m/s. What are the wavelengths of these signals?
550 kHz signal
m
1600 kHz signal
m
On FM, the frequencies range from 88.0 MHz to 108 MHz (megahertz) and travel at the same speed. What are their wavelengths?
88.0 MHz signal
m
108 MHz signal
m

Answer 1

Concepts and reason

The concepts used to solve this problem are wavelength.

First find the wavelength for AM radio signal of frequency using wavelength expression.

Again by using wavelength expression find the wavelength for AM radio signal of frequency .

Then find the wavelength for FM radio signal of frequency using wavelength expression.

Finally again by using wavelength expression find the wavelength for FM radio signal of frequency .

Fundamentals

The disturbance that transfers energy through matter or space is called wave.

Every waves have certain shape and length.

Froms of electromagnetic radiating waves make characteristic pattern as they travel through space.

The distance between the adjacent crests is called wavelength.

Here AM radio signal is the amplidtude modulation of radio signal and FM is the frequency modulation.

The expression for wavelength is,

Here, is the wavelength, is the velocity, and is the frequency.

(1)

The expression for wavelength is,

Substitute for , and for .

(2)

The expression for wavelength is,

Substitute for , and for .

(3)

The expression for wavelength is,

Substitute for , and for .

(4)

The expression for wavelength is,

Substitute for , and for .

Ans: Part 1

The wavelength for AM radio signal of frequency is .

Part 2

The wavelength for AM radio signal of frequency is .

Part 3

The wavelength for FM of frequency is .

Part 4

The wavelength for FM of frequency is .