Frequency and Velocity

[Evonne Chau 2I]

How does one find the frequency given the velocity?

[Caden Ciraulo 1J]

If given mass, once can utilize the equation, E=pc to find energy and then utilize E=h(frequency) to find frequency. Therefore, if you're given the velocity of an electron, you can find the momentum via knowing the mass of an electron is 9.109*10^-31 kg.

[Naman Jain 3F]

You can use the de Broglie equation - lambda = h/mv to first find the wavelength of the given particle using its velocity. Then use v=c/lambda to find the wavelength.

[AudreyQian1J]

Hello,

If mass is given or if the problem is talking about an electron, proton, or neutron (in which they all have rest mass), then you may use De Broglie's equation, lambda = h/p or lambda = h/(m*v) to solve for the wavelength. From there, you may use c=lambda*v to solve for frequency: v = c/lambda.

[Katryn Heine 3A]

If given frequency convert it to wavelength using the formula c=(wavelength)x(frequency). Once you have wavelength you can use the formula wavelength=h/p. P=mv so rewrite your equation as wavelength=h/(mv). Solve for v assuming you're able to find the mass.

[Tyler Olson 1E]

Using the equations E = h ν and E = pc you can derive the equation v = pc/h or v= (mv)*c/h which will make it possible to solve for the frequency. Hope that helps!

[Trisha Badjatia 2L]

I agree with what everyone else said, but I also think that velocity and frequency aren't typically asked together. Velocity pertains to particles with mass and you can use the de Broglie equation to find the wavelength, but electrons aren't guaranteed to travel at the speed of light so the c=lamba*f equation isn't always useful.

[Natalie Quilala 1I]

To find frequency from velocity, I would use the de Broglie wavelength equation, in which lambda=h/p, and p=mass*velocity. After finding lambda, you can use the c=lambda*frequency and rearrange the equation to frequency=c/lambda to solve for frequency.

[Lisa Ramos 1C]

You usually have to go through 2 different equations first. You would first start with the De Broglie equation, which is lambda (wavelength) = h/p, which is also h/mv. Since h is a constant and the mass will usually be given to you (either directly or by stating if it's a photon, electron, etc) you would find the wavelength. By finding the wavelength, you can find the frequency with the equation frequency = c / lambda. Hope this helps!

[Jieun 2C]

Another method you can use is frequency=p*c/h. p can be calculated using mass*velocity. I found this equation by substituting E in E=h*frequency with p*c from the equation E=p*c.

[Connor_Olsen_2K]

There honestly is multiple ways to do this but I would go through energy and convert to momentum then get velocity from there.

[Windell Viste 1K]

To find frequency using velocity, you can start with wavelength = h / p. p is momentum which is equal to mass times velocity, so the equation would be wavelength=h/m times p. After finding the wavelength you would rearrange the equation c=frequency times wavelength to frequency=c/wavelength :)