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| De Broglie wavelength for a particle of matter |
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We
have already seen that we can think of waves as particles and that they
can be thought of as having a mass equivalent and even a momentum - see
the photon - now
we have to look at matter as waves!
Matter has momentum 'p' - the mass multiplied by the velocity We know that pphoton = h/l So De Broglie (pronounced De Broy) proposed that any particle of matter has a wavelength and wave properties as well as particle properties. Just as a light in a photon has particle properties but is wave also, so an electron or proton (or even YOU) would have a wavelength as well as momentum!
Note that only moving particles can act like waves! They must have momentum. You will often come across questions that give you the accelerating voltage that charged particles move across and nothing else! Let us consider this: E = QV So the kinetic energy gained by an electron (having a charge 'e') moving across a potentiall difference of 'V' would be 'eV'
You should know how to do this... Lets try a question! Over what potential difference do you have to accelerate electrons for them to have a wavelength of 1.2 x 10-10 m? Click here for the answer.
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