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De Broglie Wavelength Calculator
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If a particle of mass 'm' moving with a velocity 'v' having energy 'E' then it manifests itself in the form of a wave, its wavelength would be
$\lambda$ = $\frac{h}{p}$
where h = planck's constant and
p = momentum 
This is de Broglie wave equation.
This wave will be having energy in terms of $\lambda$ as:
E = $\frac{hc}{\lambda}$
This is called De Broglie energy-wavelength relation.

De-Broglie wavelength calculator calculates energy and momentum of photon if wavelength is given and we can get the debroglie wavelength if energy or momentum is given.
 

Steps for De Broglie Wavelength Calculator

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Step 1 :  

Analyze the problem. List out the given given quantities and find out which quantity is missing.



Step 2 :  

If momentum of photon is given then use the formula


$\lambda$ = $\frac{h}{p}$


where h = Plancks constant,


p = momentum of photon.


If energy is given, then use formula


$\lambda$ = $\frac{h c}{E}$


Here E = Energy of Photon and


c = Velocity of light.


If Wavelength is given you can any of these formula and can get desired quantities of the two.



Problems on De Broglie Wavelength Calculator

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  1. Calculate the de Broglie wavelength for an electron having velocity 5 $\times$ 105 m/s.If mass is 9.1 $\times$ 10-31 Kg.


    Step 1 :  

    given: Mass m = 9.1 $\times$ 10-31 Kg,


    Velocity V = 5 $\times$ 105 m/s,


    Momentum of electron p = mv = 9.1 $\times$ 10-31 Kg $\times$ 5 $\times$ 105 m/s.


                                                 = 45.5 $\times$ 10-26 kgm/s.


     



    Step 2 :  

    If momentum of photon is given then use the formula


    $\lambda$ = $\frac{h}{p}$


           = $\frac{6.624 \times 10^{-34}}{45.5 \times 10^{-26}}$ 


           = 1.45 $\times$ 10-9 m.



    Answer  :  

    $\lambda$ = 14.5 $A^{\circ}$



  2. Calculate the momentum and energy for an electron if de-broglie wavelength is 0.24 $A^{\circ}$


    Step 1 :  

    Mass m = 9.1 $\times$ 10-31 Kg,


    Wavelength $\lambda$ = 0.24 $\times$ 10-10 m



    Step 2 :  

    Using the formula

    $\lambda$ = $\frac{h}{p}$

    Then momentum is given by


    p = $\frac{h}{\lambda}$


       = $\frac{6.624 \times 10^{-34}}{0.24 \times 10^{-10}}$


       = 2.76 $\times$ 10-26 kgm/s.


    Energy is given by


    E = $\frac{hc}{\lambda}$


       = $\frac{6.624 \times 10^{-34} \times 3 \times 10^{8}}{0.24 \times 10^{-10}}$


     = 8.28 $\times$ 10-15 eV.



    Answer  :  

    Momentum p = 2.76 $\times$ 10-26 kgm/s.

    Energy E = 8.28 $\times$ 10-15 ev.



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