De Broglie Equation v. Speed of Light Equation
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De Broglie Equation v. Speed of Light Equation
I'm having difficulty comprehending when to use De Broglie's equation to find the wavelength and when to use the speed of light equation to find the wavelength. Are there certain conditions for the different equations that I should be aware of? Or any given information/keywords used in a problem that would be an indicator?

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Re: De Broglie Equation v. Speed of Light Equation
generally, you would use the speed of light equation of electromagnetic traditions, light, and the de Broglie equation for things with mass, such as electrons and basketballs

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Re: De Broglie Equation v. Speed of Light Equation
When you are finding the wavelength of something that has mass is when you should be using de Broglie, like an electron or an object. Therefore, you cannot use this to calculate the wavelength of photons because they have no mass and must use the other equation to find the wavelength of light.

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Re: De Broglie Equation v. Speed of Light Equation
Hi! The speed of light equations are used when you want to find the wavelength/frequency of a photon, so you can't use it for other objects. You can instead use DeBroglie's equation to find the wavelength! Also, sometimes the question asks if an object's wavelength is detectable/not detectable, which I typically associate with DeBroglie's equation. Hope this helped!

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Re: De Broglie Equation v. Speed of Light Equation
Anna Martin 2l wrote:When you are finding the wavelength of something that has mass is when you should be using de Broglie, like an electron or an object. Therefore, you cannot use this to calculate the wavelength of photons because they have no mass and must use the other equation to find the wavelength of light.
That makes sense! Thank you

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Re: De Broglie Equation v. Speed of Light Equation
Chanel Mao 2F wrote:Hi! The speed of light equations are used when you want to find the wavelength/frequency of a photon, so you can't use it for other objects. You can instead use DeBroglie's equation to find the wavelength! Also, sometimes the question asks if an object's wavelength is detectable/not detectable, which I typically associate with DeBroglie's equation. Hope this helped!
That's a good indicator! Thanks for your help.

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Re: De Broglie Equation v. Speed of Light Equation
You will generally need to use de Broglie's Equation when it comes to things with mass, velocity, or momentum, like an electron or other particle. Things like photons don't have mass, which is when you would use the speed of light equation.

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Re: De Broglie Equation v. Speed of Light Equation
Yes, put simply, De Broglie Equation is used on things with mass while Speed of Light is used on photons which are massless.

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Re: De Broglie Equation v. Speed of Light Equation
The de Broglie equation is only applicable for objects with mass, as the equation involved momentum which is mass * velocity. The speed of light equation only applies to light, such as the emission from atomic spectroscopy or electromagnetic radiation.

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Re: De Broglie Equation v. Speed of Light Equation
Hi, I too became confused as to when to use the speed of light and electromagnetic equations such c=lamda *v, E=hc/lamda, E=hv and went to use the De Broglie Equation (lamda= h/4pi). However, I have come to the realization that the speed of light equation is for photons which are in the electromagnetic spectrum. Photons do not have mass, so mass is not relevant and is why we do not see mass in any of the equations. However for objects that are not photons such as electrons, neutrons, protons, and even cars, (anything with velocity and mass) mass and velocity are important aspects of it. De Broglie incorporates mass and velocity and therefore is the better equation to use to find wavelength. However, if mass and velocity are not relevant such as photon, use the speed of light equation.

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Re: De Broglie Equation v. Speed of Light Equation
Debrogile's equation is used to find the wavelength and momentum of small objects such as electrons, protons, and neutrons, while the speed of light equation is used to find the wavelength and frequency of light.

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Re: De Broglie Equation v. Speed of Light Equation
Since photons have no mass, the speed of light equation can be used to find wavelength of photons. However, when dealing with objects such as cars, baseballs, or electrons that involve mass, you'd use DeBroglie's equation. The wavelength of small objects are detectable such as electrons and neutrons, but not detectable for cars, balls, etc.

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Re: De Broglie Equation v. Speed of Light Equation
To find wave length, you use the De Brogile equation

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Re: De Broglie Equation v. Speed of Light Equation
The de Broglie equation gives you the wavelength and momentum of something with mass. Since photons don't have mass, you would have to use the speed of light equations.

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Re: De Broglie Equation v. Speed of Light Equation
The equations for the speed of light refer to protons, so any other object that has mass can have the wavelength or frequency calculated by utilizing the De Broglie equation.
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