## DeBroglie

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

Jamie Reniva 1J
Posts: 14
Joined: Wed Nov 15, 2017 3:00 am

### DeBroglie

How do we know when to use the DeBroglie equation? I'm still a little bit confused where to get "p" in the equation.

Isabelle De Rego 1A
Posts: 40
Joined: Fri Apr 06, 2018 11:02 am

### Re: DeBroglie

You only use De Broglie when you are finding the wavelength of something with a mass( wavelength = h/p) . p=mv, where m is mass and v is velocity. So, they would probably give you the two of the three variables and then you would solve for the third one.

004985802
Posts: 27
Joined: Fri Feb 02, 2018 3:00 am

### Re: DeBroglie

you would use this to measure the wavelength of a moving object that has mass in order to determine whether it has wavelike properties

Nick Griffin 1K
Posts: 3
Joined: Fri Apr 06, 2018 11:03 am

### Re: DeBroglie

DeBroglie determines the wavelength/wavelike properties of things with mass. So you don't use it for light, just things with mass (and velocity since you need momentum which is mass x velocity). You would probably use it in a problem to find wavelength, mass, or velocity (h is a constant)

AnnaYan_1l
Posts: 96
Joined: Fri Apr 06, 2018 11:05 am
Been upvoted: 1 time

### Re: DeBroglie

I agree with the people above! p (which means momentum) is = to (mass)(velocity) which is usually given to you in some shape or form in the question. It is for a moving object (not light)

Shimran Kumar 1C
Posts: 30
Joined: Fri Apr 06, 2018 11:03 am

### Re: DeBroglie

Light does have a momentum. The photons however do not have a mass. So I suppose if the problem gave you a value for the momentum (p), you could use the de Broglie wavelength as normal. Otherwise, this equation doesn't work for light.

Endri Dis 1J
Posts: 33
Joined: Fri Apr 06, 2018 11:02 am

### Re: DeBroglie

Can someone give an example of a practice problem that uses the DeBroglie Equation?

Nicole Shak 1L
Posts: 35
Joined: Wed Nov 22, 2017 3:03 am

### Re: DeBroglie

In class the example was to find the wavelength of a 0.1 kg baseball traveling at a velocity of 35 m/s. You would use the DeBroglie Equation, wavelength=h/m*v to solve this.