Sound Waves vs EM Waves-Difference between Sound Waves and EM Waves

This page compares Sound Waves vs EM Waves and mentions difference between Sound Waves and EM Waves.

Sound Waves

Sound waves generation

The sound waves are mechanical waves which are produced by mechanical vibrations. They need material medium such as air, water, steel etc. for propagation.

Sound waves are longitudinal waves in which individual particles of the medium move in a direction parallel to direction of propagation of disturbance. Here the particles do not move from one place to the another but they simply oscillate back and forth about their position of rest. The figure-2 depicts sound wave generation using vibrating tuning fork.

There are many applications of sound waves which include musical instruments, ultrasound cleaners, earth explorations for minerals/petroleum, sonar etc.

EM (Electro-Magnetic) Waves

EM waves generation

The figure-1 depicts generation of EM (Electromagnetic) waves using simple dipole antenna. Similar concept can be applied to other types of antennas also.

EM waves are called transverse waves in which particles do not oscillate along the line of wave propagation but oscillate up and down about their mean position as the wave travels.

There are many applications of EM waves which include radio broadcasting, infrared remote controls, microwave oven, mobile phones, X-rays, skin tightening, Spectroscopy etc.
Refer EM waves >>.

Sound Waves EM Waves
They are produced by mechanical vibrations. They are produced by accelerating charged particles.
They are created by musical instruments, speakers, human beings, tuning forks or any vibrating objects etc. They are created by wires carrying currents, blackbody radiation etc.
Sound waves can not propagate through vacuum. EM waves propagate through vacuum and travel with the speed of light (i.e. 3 x 108 m/sec).
Sound waves can not excite atoms. EM waves can excite atoms.
Sound waves (of longitudinal type) are not polarizable. EM waves are polarizable.
Speed of sound waves depend on air temperature. Speed of EM waves do not depend on air temperature.
Sound waves can not travel through the vacuum. EM waves can travel through the vacuum.


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