## Rearranging De Broglie Equation

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

Alessia Renna 1D
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### Rearranging De Broglie Equation

How would you rearrange the De Broglie Equation in order to calculate velocity using wavelength, mass, and planck's constant?

Jordan Tatang 3L
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### Re: Rearranging De Broglie Equation

Hi!

So the De Broglie Equation is shown on the formula sheet as
(wavelength) = h/p

p = momentum which is (mass)(velocity)

Therefore, you can rewrite the equation as
wavelength = h/(mass)(velocity)

If you multiply both sides by velocity and then divide both sides by wavelength you end up with

velocity = h/(mass)(wavelength)

Hopefully this helps!

Posts: 126
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### Re: Rearranging De Broglie Equation

The De Broglie equation is wavelength = planck's constant over momentum. Momentum is equal to mass times velocity. So if you write, wavelength=h/mv and then isolate the velocity, you should get what you're looking for. It should come out to be v=h/(wavelength times mass)

Lisa Seidl 3H
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### Re: Rearranging De Broglie Equation

The original equation is (lambda)=h/mv
To rearange this, you'd want to solve for v before inputting any numbers since this makes the process a lot easier. After rearranging and solving for v, your new equation should be v=h/m(lambda)

Rob Tsai 2F
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### Re: Rearranging De Broglie Equation

De Broglie's equation: (lambda) = h/p, where h= Planck's constant and p= momentum.

It can be further simplified to (lambda) = h/(mv), where m= mass and v= velocity, as momentum is (mass)(veloctity).

Then, we can do some relatively simple algebra to solve for velocity (v):
(lambda) = h/(mv)
(v)(lambda) = (v)(h)/(mv), where we multiply both sides by velocity (v) to isolate it to one side.
(v)(lambda) = h/m, as velocity (v) in the numerator and denominator cancel out.

Hope this helps!

Aydin Karatas 1F
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### Re: Rearranging De Broglie Equation

The De Broglie Equation states that λ=h/p, where p=mv.

Therefore, we know that λ=h/mv.

If λ and m are given and knowing that h is a constant, we can isolate for v with v=h/λm.

The main thing to keep in mind with De Broglie conceptually is that small particles exhibit wave-like properties.

Hope this helps!

Lorraine Medina 3E
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### Re: Rearranging De Broglie Equation

Hi! The given equation for De Broglie is λ=h/p (where h is Planck's constant and p is momentum), we also know that p=mv (where m is mass and v is velocity). Therefore, we can substitute p in the original De Broglie equation for mv. From there, you get λ=h/mv. You can solve for velocity by multiplying both sides of the equation by mv, then dividing both sides by mλ. From there, you are left with v=h/λm.

Michael Sun Dis 3G
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### Re: Rearranging De Broglie Equation

If you multiplied both sides of the equation by velocity, then divided both sides by wavelength, you'd end up with v = h / mλ.

Sophia Kalanski 1A
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### Re: Rearranging De Broglie Equation

Hello!

So we know that the De Broglie Equation is originally (wavelength)=h/mv

to rearrange it so that you are trying to find the velocity, you would multiply v by both sides to cancel it out from the right side and then divide the wavelength by both sides.
You end up with v=h/(m*wavelength)

Angel Gutierrez 2E
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### Re: Rearranging De Broglie Equation

When you have values with a neg exponent and they are the denominator in the equations, do you change the negative exponents as a positive since they become part of the denominator?

Jiapeng Han 1C
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Joined: Wed Sep 30, 2020 9:50 pm

### Re: Rearranging De Broglie Equation

According to De Broglie's equation: wavelength=planck constant/momentum.
Momentum=mass*velocity
As a result, wavelength=planck constant/(mass*velocity), so velocity=planck constant/(mass*wavelength).

Kayla Booker 1F
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### Re: Rearranging De Broglie Equation

Since de broglie’s equation is wavelength =h/mv, you multiple v to both sides then divide by wavelength to get v=h/m(wavelength)

Jason_John_2F
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### Re: Rearranging De Broglie Equation

You want to rearrange the equation to isolate the v which can be done simply by multiplying both sides by v and dividing both sides by λ to get v=h/mλ

Emma Ide 2E
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### Re: Rearranging De Broglie Equation

DeBroglie's equation can be rearranged in many ways to find other values.
wavelength=h/p
p= mv and
E=pc, so
pc=h(c/wavelength)
which gives the wavelength equation
these equations can all be derived from each other

Mari Williams 1K
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### Re: Rearranging De Broglie Equation

Will we likely have to derive these equations during the midterm since they're not on the equation sheet?

505598869
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### Re: Rearranging De Broglie Equation

wavelength(lambda) = planck's constant(h) / momentum(p)
p = mass x velocity
you can plug in mv for p in the wavelength equation and isolate v
you would end up with

v = h/m(lambda)

Abraham De Luna
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### Re: Rearranging De Broglie Equation

(velocity)= h/(mass)(wavelength)

Simran Bains 2C
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### Re: Rearranging De Broglie Equation

(wavelength)=h/p
p=(mass)(velocity)
(wavelength)=h/(mass)(velocity)