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# What is this formula watch

1. Hi, can someone tell me what this formula is please?

Tried typing it into wolfram alpha but it does not recognise it.

Thanks.
2. https://www.wikiwand.com/en/Beer%E2%80%93Lambert_law

Specifically for uniform attenuation.
3. (Original post by alow)
https://www.wikiwand.com/en/Beer%E2%80%93Lambert_law

Specifically for uniform attenuation.
Thanks! Do you learn this in first year chem?
4. (Original post by AishaGirl)
Thanks! Do you learn this in first year chem?
I learned it in my first year cell biology course.
5. (Original post by alow)
I learned it in my first year cell biology course.
Just a quick follow up question you might be able to help me with.

What is the best way to solve this first order ODE for intensity if light transmitted through the length of solution where the original intensity is

Should I integrate it using the boundary condition of the original light intensity? So at ?

Thank you.
6. (Original post by AishaGirl)
Just a quick follow up question you might be able to help me with.

What is the best way to solve this first order ODE for intensity if light transmitted through the length of solution where the original intensity is

Should I integrate it using the boundary condition of the original light intensity? So at ?

Thank you.
What is ? And I assume you mean for the original intensity.

If is the coordinate along the length of the tube, then integration like you said would be fine:

7. (Original post by alow)
What is ? And I assume you mean for the original intensity.

If is the coordinate along the length of the tube, then integration like you said would be fine:

Yeah it's through the total length.

Thanks.
8. (Original post by alow)
What is ? And I assume you mean for the original intensity.

If is the coordinate along the length of the tube, then integration like you said would be fine:

I think you made a typo there, isn't it meant to be ?

You put a 1...
9. (Original post by AishaGirl)
I think you made a typo there, isn't it meant to be ?

You put a 1...
Where are you getting that extra I from? divided through by then used as a dummy variable of integration.
10. (Original post by alow)
Where are you getting that extra I from? divided through by then used as a dummy variable of integration.
Yes sorry I was a bit lost. Starting to invent variables from thin air lol.

Thanks again.
11. (Original post by AishaGirl)
Yes sorry I was a bit lost. Starting to invent variables from thin air lol.

Thanks again.
No problem

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