The Electromagnetic Spectrum - Radio Waves

Radio Waves

Radio Waves in the Electromagnetic Spectrum

The radio waves are the electromagnetic waves which have the longest wavelengths in the electromagnetic spectrum, so long that if you were to look at the sky with a radio telescope, instead of point sources like stars and clouds, you can see entire regions that promote star formation, distant quasars and probable remnants of supernovas. These waves have low energy levels and low frequencies ranging from around 3 kHz to around 300 GHz.

Due to their wide range, they are mostly used in communication systems like broadcasting, communication satellites, computer networking systems, radar and other kinds of navigation. How do you think FM/AM Radio works? Simply put, radio waves are generated and propagated by radio transmitters. These waves are then received by a radio receiver (tuned to a particular frequency/wavelength using a radio antenna) which then converts these into mechanical waves which are played through radios and different sounds.

Different bands in Radio spectrum 

Radio spectrums can be divided further into 9 bands depending on their frequency and wavelength ranges as follows

Extremely Low Frequency (ELF)

Frequency Range: less than 3kHz

Wavelength Range: greater than 100km

Very Low Frequency (VLF)

Frequency Range: 3kHz to 30 kHz

Wavelength Range: 10km to 100km

Low Frequency (LF)

Frequency Range: 30 kHz to 300 kHz

Wavelength Range: 1km to 10km

Medium Frequency (MLF)

Frequency Range: 300kHz to 3MHz

Wavelength Range: 100m to 1km

High Frequency (HF)

Frequency Range: 3MHz to 30 MHz

Wavelength Range: 10m to 100m

Very High Frequency (VHF)

Frequency Range: 30 MHz to 300 MHz

Wavelength Range: 1m to 10m

Ultra High Frequency (UHF)

Frequency Range: 300 MHz to 3GHz

Wavelength Range: 10cm to 1m

Super High Frequency (SHF)

Frequency Range: 3GHz to 30 GHz

Wavelength Range: 1cm to 10cm

Extremely High Frequency (SHF)

Frequency Range: 30 GHz to 300 GHz

Wavelength Range: 1mm to 1cm

Radio waves are even used in the field of astronomy. Although they have low energies, even these are tappable. Learn more about radio waves with our faculty at BYJU’S.

Practise This Question

A potential difference of V is applied at the ends of a copper wire of length l and diameter d. On doubling only l, drift velocity