Calculating velocity when given De Broglie wavelength. Moderators: Chem_Mod wavelength of × m? I'm not quite sure how to manipulate the equation to solve for velocity? Top mass x velocity = h/wavelength. Apr 11, To calculate the de Broglie wavelength for a particle, or for a tennis ball for that matter, just use the equation. p=hλ, where So, starting with the electron that travels at 10% of the speed of light. The speed of light can be The mass of an electron is m=⋅10−31kg. Now plug your values into the main. λ= De Broglie Wavelength ; m= mass ; v= velocity ; h = Plank's constant This De Broglie equation is based on the fact that every object has a wavelength.
I don't know, does it? No, it's not even Catholic. Shoulda went to the beach today. But wait, doesn't light really have mass?
It's got momentum so it's gotta have mass.
The Speed of a Wave
It has momentum so it must have mass. Everyone just calm the heck down. You see, the worst part of all this wasn't that my joke bombed, it was that I actually managed to confuse people by telling it.
My students had read that light has momentum and they were right, light really does have momentum. But then I come to class and I'm all like, hey, guess what, light has no mass. Now my students are thinking to themselves, dude, but P equals MV.
In other words, if momentum equals mass times velocity, how could light, which has no mass, ever have momentum? Well, I had to break it to my students that P equals MV isn't really accurate for things that travel close to the speed of light. Sometimes a wave encounters the end of a medium and the presence of a different medium. For example, a wave introduced by a person into one end of a slinky will travel through the slinky and eventually reach the end of the slinky and the presence of the hand of a second person.
One behavior that waves undergo at the end of a medium is reflection. The wave will reflect or bounce off the person's hand.
Deriving the de Broglie Wavelength
When a wave undergoes reflection, it remains within the medium and merely reverses its direction of travel. In the case of a slinky wave, the disturbance can be seen traveling back to the original end. A slinky wave that travels to the end of a slinky and back has doubled its distance. That is, by reflecting back to the original location, the wave has traveled a distance that is equal to twice the length of the slinky. Reflection phenomena are commonly observed with sound waves.
When you let out a holler within a canyon, you often hear the echo of the holler.
The sound wave travels through the medium air in this casereflects off the canyon wall and returns to its origin you. The result is that you hear the echo the reflected sound wave of your holler.
Physclips: Sound wave equation
A classic physics problem goes like this: Noah stands meters away from a steep canyon wall. He shouts and hears the echo of his voice one second later. What is the speed of the wave? Remember, when there is a reflection, the wave doubles its distance. In other words, the distance traveled by the sound wave in 1 second is equivalent to the meters down to the canyon wall plus the meters back from the canyon wall.
- A-level Physics (Advancing Physics)/Electron Behaviour as a Quantum Phenomenon
- CHEMISTRY COMMUNITY
- Matter wave