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Q.
Matter waves are:
Dual Nature of Radiation and Matter
Solution:
it is a wave associated with particles revolving in an atom around nucleus.
De broglie named these waves as matter waves or De Broglie's waves.
its wavelength is calculated from wavelength $\lambda= h / mv$,
where, $h$ is plank constant.
This theory mainly conveys the wave nature of light having energy given by plank $E = hv$.
($v$ is frequency of radiation).
These waves do not require any material medium for it propagation.
it is coming in mainly non relativistic theory.