## When do we use the Einstein Equation?

$E=hv$

Donavin Collins 1F
Posts: 66
Joined: Sat Sep 14, 2019 12:16 am

### When do we use the Einstein Equation?

Hello :) I'm kinda confused about when exactly we use the Einstein Equation. Also, is it something that's used a lot? Thank you!

TarynD_1I
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

### Re: When do we use the Einstein Equation?

I'm pretty sure we use E=hv to find the energy of a photon

Aliya Jain 2B
Posts: 101
Joined: Wed Sep 11, 2019 12:16 am

### Re: When do we use the Einstein Equation?

Im pretty sure it's used a lot because you can also isolate frequency in λv=C and subsitute it back into E=hv to find wavelength.

lilymayek_1E
Posts: 107
Joined: Sat Aug 17, 2019 12:16 am

### Re: When do we use the Einstein Equation?

Like Taryn said, we use it to find energy/photon, substitute it in the rydberg equation (the equation used to find frequency, energy,et.c. of light when electrons go up/down quantum levels) & c=v(wavelength. it's used a lot; besides c=v(wavelength) I think it's probably one of the most commonly used (especially since we're talking about photons/electrons a lot) :)

mayarivers3I
Posts: 52
Joined: Wed Sep 18, 2019 12:18 am

### Re: When do we use the Einstein Equation?

The Einstein equation is used to solve for energy of an electron, but can also be useful to solve for other things such as frequency because that equation is C=(lambda)v.

vanessas0123
Posts: 100
Joined: Wed Sep 11, 2019 12:17 am

### Re: When do we use the Einstein Equation?

It is used to solve for the energy of the photon. You also use it with the C=λν equation a lot.

Emil Velasco 1H
Posts: 96
Joined: Wed Nov 21, 2018 12:19 am

### Re: When do we use the Einstein Equation?

E = hv is used to solve for the energy of an electron.

Sometimes you are not given v (frequency) therefore you must use c = λν, substituting the v in E=hv for v = c/ λ:

so E = hc/ λ

Abraham De Luna
Posts: 84
Joined: Sat Sep 14, 2019 12:16 am

### Re: When do we use the Einstein Equation?

We would use the equation in order to find the energy of a photon. However, it does have other uses.

Sean1F
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Joined: Sat Sep 07, 2019 12:16 am

### Re: When do we use the Einstein Equation?

How often would you have to rearrange this equation to find other quantities? Should this be practiced?

Connor Ho 1B
Posts: 102
Joined: Sat Aug 17, 2019 12:17 am

### Re: When do we use the Einstein Equation?

E = hv is used in general to find the energy of a photon, although it can also be interpreted to find the energy required to remove an electron. On the topic of quantum, E = hv is most likely going to be a major equation.

Connor Ho 1B
Posts: 102
Joined: Sat Aug 17, 2019 12:17 am

### Re: When do we use the Einstein Equation?

Sean1F wrote:How often would you have to rearrange this equation to find other quantities? Should this be practiced?

The rearrangment of this equation would be most likely to find the energy required to remove an electron, or finding the wavelength of a photon/electron. It should be practiced as I believe finding these two quantities will also be common on the topic of quantum.

kristi le 2F
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

### Re: When do we use the Einstein Equation?

The equation E=hv can also easily be rearranged to be used to solve for v as well if you know Energy. Planck's constant will always be the same.

ramiro_romero
Posts: 90
Joined: Sat Sep 07, 2019 12:16 am

### Re: When do we use the Einstein Equation?

When relating energy of a photon to frequency, we use Einsteins equation. And if kinetic energy=0, we can also use it for the energy required to remove an electron. So, E = hv is used for relating the energy of a photon to its frequency, (remember that energy of a photon and its frequency are directly proportional)

105289321
Posts: 49
Joined: Sat Sep 07, 2019 12:15 am

### Re: When do we use the Einstein Equation?

You would use it to calculate the energy of an electron

ramiro_romero
Posts: 90
Joined: Sat Sep 07, 2019 12:16 am

### Re: When do we use the Einstein Equation?

E=hv will give you the energy of a photon. You should use it when finding frequency given energy or to find energy when given frequency.