Hi, I’m a little bit confused about the use of equations.
Which equations do we use for solving for particles, and which are for light? I need some help getting them straightened out in my head.
Thanks!
Equations
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Re: Equations
We went over this a little bit in our discussion week so hopefully this will help.
1)Energy of a photon: E=hv and c=v(lambda) -These are commonly used in questions concerning the photoelectric effect.These are used for photons only.
2) De Broglie's Equation: lambda=h/p(momentum) -Although this also has an equation that solves for wavelength it is not used for photons but for particles. Usually you know when to use this equation because it will give you variables such as mass and volume. If these are not given it is a good indicator that you do not need to use this equation.
3) Photoelectric Effect: E=hv-(work function)= 0.5mv(squared) -This equation is also used when working with photons.
Our TA advised us to pick the equations we use based on the information given in the problems. Usually you only use De Broglie's if mass or volume are involved.
1)Energy of a photon: E=hv and c=v(lambda) -These are commonly used in questions concerning the photoelectric effect.These are used for photons only.
2) De Broglie's Equation: lambda=h/p(momentum) -Although this also has an equation that solves for wavelength it is not used for photons but for particles. Usually you know when to use this equation because it will give you variables such as mass and volume. If these are not given it is a good indicator that you do not need to use this equation.
3) Photoelectric Effect: E=hv-(work function)= 0.5mv(squared) -This equation is also used when working with photons.
Our TA advised us to pick the equations we use based on the information given in the problems. Usually you only use De Broglie's if mass or volume are involved.
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Re: Equations
amogha_koka3I wrote:Will we be required to know how to derive De Broglie's Equation?
No, De Broglie's Equation is given on the "Constants and Equation" page, but it is not labeled as De Broglie's equation.
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Re: Equations
With all the equations in this section how do we know when a v is frequency and when it represents velocity?
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Re: Equations
RoopshaChatterjee 1G wrote:With all the equations in this section how do we know when a v is frequency and when it represents velocity?
In response to your question, there are different notations for frequency and velocity. Frequency is denoted with the Greek letter nu, while velocity is denoted with the letter v.
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Re: Equations
I also heard that the test is going to be more conceptual, so I think as long as you know how the equations relate to each other as well as what the variable/parameters represent, you should be fine for the most part.
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