Malus' law

Рет қаралды 190,138

9 жыл бұрын

An explanation of Malus' law, used to calculate the light intensity transmitted through a polarising filter.
By Cowen Physics (www.cowenphysics.com)

Пікірлер: 70

@trevorsmith5909 4 жыл бұрын

This is making so much more sense than my physics text!

@klevisimeri607 2 жыл бұрын

YEssssssss!

@rishitachawla2574 2 жыл бұрын

Agreed

@quinntoppolis6454 8 жыл бұрын

Thank you for the explanation... I was preparing to kidnap my instructor because the text didn't explain this.

@Vegeta2169 6 жыл бұрын

Quinn Toppolis same

@shwetai4641 9 жыл бұрын

Wonderfully concise and easy to follow. Thank you so much!

@BobaShark4067 3 ай бұрын

Straight to the point explanation. Thank you so much!

@avishekacharyaav4924 2 жыл бұрын

True legend thanks alot my head was goint to brust you just saved me. I was trying for it to pass through analyzer twice individually and couldn't think of it

@javedfaizal5473 Жыл бұрын

Concise and clear- thank you very much!

@sethmurphy6771 9 жыл бұрын

great, concise and helpful.

@shteam7294 3 жыл бұрын

Thank you ! well explained especially the formula for A to I

@MAVrikrrr 11 ай бұрын

Thanks, now I understand why it's cos square. In my tought experiment it was just cos and I was really confused to see cos square in the Malus's law.

@Tonnidas 6 жыл бұрын

You have been blessed!

@abdelz1617 2 жыл бұрын

Great video, thank you!

@a.meforyou 5 ай бұрын

Where did the cosine come from?

@annsha7198 6 жыл бұрын

I finally get it, thank you!!!!

@saharkaouk3692 8 жыл бұрын

awesome explanation!

@hirmaypatel1692 8 жыл бұрын

Amazing, thank you

@Sara-om3fe 2 жыл бұрын

The way my textbook exaplained this idea was so confusing. Thank you for this video!

@Er-Basit 2 жыл бұрын

Yeah dear so simple ...

@bhumikasuniquearts407 5 ай бұрын

Thankyou sir, u made it easy to understand...

@BigSmokeEnthusiast Жыл бұрын

New sub. Ur a life saver!!

@sameeraabida8804 6 жыл бұрын

Thanks a lot man! Thankyou you so much...

@burninredcrab10 8 жыл бұрын

Thanks a ton!

@luzbautista6716 4 жыл бұрын

does this apply to any light?

@Tony-uu9hs 2 жыл бұрын

It’s a shame how I understood an explanation from a foreigner teacher and not from my arab ppl. Thank you so much!!

@sciencemanguy 7 жыл бұрын

Question about Malus's Law: Suppose I had 3 filters lined up on the x axis. The first 2 filters follow the exact same principles you outlined above (2nd filter has pheta of 30*), but the third one is now perpendicular to the first filter. As you mentioned earlier in the video, this would result in no light getting through. But here, after we get the 2nd polarised light [the final answer you had at the end of the video], that new plane of vibration is no longer perpendicular to the third filter [when the third filter was perpendicular to the polarized light from the initial polarizre], thus, should produce an intensity that is not 0. But that is not what I see when I experiment with it. What is going on?

@Vegeta2169 6 жыл бұрын

sciencemanguy try this: put two polarizers at a 90° angle of each other. You won't see light. Put a third polarizer in between in an angle thats 0°< x < 90° and adjust that angle and you will see light coming through.

@MAVrikrrr 11 ай бұрын

When you have 3 filters, the intensity formula is the same: A2=A0*cos(t1)*cos(t2) Where A0 is initial amplitude, t1 is an angle difference between 1st and 2nd filter, t2 is an angle between 2nd and 3rd filter. Let's say you have filters with angles 0, 30 and 90 degrees. t1 = 30, t2 = 60. Does it make sense?

@yashwanthkumar6299 6 жыл бұрын

Well Said Gentlemen Your Good

@VishalMaharathy 5 жыл бұрын

Very well explained

@manhaabdellah2682 2 жыл бұрын

Short amd simple thankss

@axellrxeez6058 2 жыл бұрын

Very informative thank you

@chips6072 9 жыл бұрын

Thankyou!!!

@AwesomeDolphin 4 жыл бұрын

Thank you!

@shanaya5855 7 жыл бұрын

oh now i got it nice teaching

@iplay7816 8 жыл бұрын

Am I correct to believe this isn't part of the spec for the OCR Physics A Depth Paper tomorrow?

@CowenPhysics 8 жыл бұрын

The principles are relevant for the new spec, but the law itself and equation are not. In other words, you should know how the light transmitted varies through a polaroid, but you won't need to calculate it.

@iplay7816 8 жыл бұрын

Thankyou very much! You have been great help to me throughout the year.

@MrRaisin56 7 жыл бұрын

very useful tyvm

@sonalsinha710 7 жыл бұрын

good explanation

@nimrod4463 5 жыл бұрын

cool, thank you

@bikdigdaddy 2 жыл бұрын

Thanks for it

@ashoka5177 7 жыл бұрын

nice bro

@madhurrao4415 6 жыл бұрын

Thanks 😊

@bangimallikarjuna9501 3 жыл бұрын

Super bro .....🙏

@yamanyucel2475 7 жыл бұрын

Is not the Intensity of the incident light halves when passes the first polarizer?

@vicponchog3071 6 жыл бұрын

It is, he missed that

@aashishanthony 5 жыл бұрын

yeah it does.....I becomes I/2

@klaudiorka2106 Жыл бұрын

Why this unit W m-2 and not A?

@mashal07- 5 ай бұрын

its Intensity=power/area so W/m^2 which is = Wm^-2

@manansahu1501 6 жыл бұрын

Oohhh good

@brightuser8843 2 жыл бұрын

Subbed ✋

@rajchauhan-dj4qz 4 жыл бұрын

Very smart

@jacobvandijk6525 8 ай бұрын

And replace A by E (= the electric field of light) and you know it all. Because the polarization of light is determined by the E-field only.

@attaurrehman8387 2 жыл бұрын

My exam is in 7 hours wish me luck🤞

@nekhilr4210 3 жыл бұрын

nice

@samk6042 5 жыл бұрын

My teacher made us watch this xD

@jerrylacefield774 7 жыл бұрын

If I,0 = 300 W/m^2 and it's unpolarized, when it passes through the first filter, it should be halved. So I,1 = 300/2 = 150 W/m^2. Then you pass the light beam through the second polarizer, I,2 = 150 W/m^2 * cos^2(30 deg) = 113 W/m^2. Video was helpful after that but he completely forgot about taking the average of the unpolarized light which is 0.5*I

@srushtikadam2156 7 жыл бұрын

Jerry Lacefield I was looking for an explanation as to why the light upon passing through the first polariser gets halved. Can you please explain a bit further?

@haroldkennethrollon6986 7 жыл бұрын

why o.5?

@vendorf 6 жыл бұрын

I realize I am late to the party, but I'm posting a response for anybody else who may need it: All light can be said to be made up of a vertical and horizontal component for any given ray. As unpolarized light in equally likely to vibrate in any direction, this thus means that the light has net equal vertical and horizontal components (IE, each make up 50% of its intensity). As such, for the first polarizer that the light passes through only the component that aligns with the polarizing axis will make it through, eliminating all of one component (horizontal or vertical) and in turn halving the intensity.

@diegotorres1264 5 жыл бұрын

Malus is Law

@Madnesstein 3 жыл бұрын

This is wrong, the intensity after the first filter is halved.

@willanderson3224 9 жыл бұрын

My teacher mocks anyone who pronounces the S. He insists it's pronounced "Maloos" haha. I wonder who's right???

@CowenPhysics 9 жыл бұрын

Will Anderson Probably him! Certainly Wikipedia thinks there shouldn't be a trailing 's'...

@arousedsquirrel2429 8 жыл бұрын

+Will Anderson Fuck the teacher that mocks his/her students.

@harrynix98 9 жыл бұрын

*Malus'

@akashpathirage9748 2 жыл бұрын

Your explanation is wrong. I0 would halve after passing through the first filter. Probably should check what you are explaining before you post it. Gonna confuse a lot of students.

@CowenPhysics 2 жыл бұрын

You are correct. I made a mistake in the video when I describe I0 as the intensity of light incident on the first polaroid, but it should be the intensity of the polarised light.