Question

AM radio signals broadcast electromagnetic radiation at frequencies between 640 kHz and 1.20 MHz.

(a) What is the shortest wavelength of an AM radio signal?
in m

(b) What is the longest wavelength?
in m

Answer 1

The shortest wavelength of an AM radio signal is 250 m

The longest wavelength of an AM radio signal is 468.75 m

Step-by-step explanation:

`\\u=(c)/(\lambda)`

where,

`\\u`= Frequency of wave =

c = speed of light =
`3* 10^8m/s`

`\lambda` = wavelength

As we can see that frequency and wavelength are inversely proportional to each other. So wave with high frequency will have shorter wavelength and wave with lower frequency will have longer wavelength.

a) The shortest wavelength of an AM radio signal:

`\\u= 1.20 MHz.=1.20* 10^6Hz=1.20* 10^6 s^(-1)`

`MHz=10^6 Hz`

`\lambda =(c)/(\\u)`

`=(3* 10^8m/s)/(1.20* 10^6)=250 m`

b) The longest wavelength of an AM radio signal:

`\\u=640 kHz=640,000 Hz=640,000 s^(-1)`

`kHz=1000 Hz`

`\lambda =(c)/(\\u)`

`=(3* 10^8m/s)/(640,000 s^(-1))=468.75 m`