Physics halp! (1 Viewer)

[hscishard]

Yea I have.
I always used an equal sign, so..

 

[muzeikchun852]

The frequencies of the waves don't change as they pass through mediums with different refractive indexes.

but this only applies to normal light.

 

[ohexploitable]

If frequency changes...Then wavelength and velocity must be different.

Never seen that symbol before.

No, velocity is constant, frequency and wavelength changes but their product is a constant, hence, frequency is inversely proportional to wavelength.

Only in a vacuum btw.

 

[ohexploitable]

but this only applies to normal light.

I think we're misunderstanding each other lol.

When green light enters the glass, it's wavelength is lowered but it's frequency remains constant. Same for yellow light.

 

[muzeikchun852]

No, velocity is constant, frequency and wavelength changes but their product is a constant, hence, frequency is inversely proportional to wavelength.

Only in a vacuum btw.

remember the answer is something like colour changes, but i just cant remember wats exactly.

 

[hscishard]

No, velocity is constant, frequency and wavelength changes but their product is a constant, hence, frequency is inversely proportional to wavelength.

Only in a vacuum btw.

I honestly don't get you sometimes.

f=v/wave

f remains constant. But if f changes, it's a different wave. But if f changes, then either the velocity or wavelength changes.

OMG. Did you have to post this question. Confusing.

 

[muzeikchun852]

anyone has the prelim dot point physics?

 

[ohexploitable]

I honestly don't get you sometimes.

f=v/wave

f remains constant. But if f changes, it's a different wave. But if f changes, then either the velocity or wavelength changes.

OMG. Did you have to post this question. Confusing.

We're talking about different things, you're still talking about the original question, I'm talking about the proportionality of frequency and wavelength of the electromagnetic spectrum in relation to velocity in a vacuum.

 

[hscishard]

We're talking about different things, you're still talking about the original question, I'm talking about the proportionality of frequency and wavelength of the electromagnetic spectrum in relation to velocity in a vacuum.

Ooo. I really do have reading problems

 

[stevey6404]

Yellow is faster because it's refracting at an angle less than green, hence faster. The greater the angle, the slower (greater the change) the light will travel at.

Incase you doubt me or want a source:
http://www.optics4kids.com/teachersparents/articles/refractionoflight.html
Search "The greater the change in velocity and wavelength, the greater the change in direction."

 

[hscishard]

But VIPER just made an awsome proof.

+ you had to work with the only given information. (Even though they aren't correct)

 

[mirakon]

I'm quite sure that this question has been sorted out now, so why is this thread still alive? Here is my proof again for convenience:

Via Snell's Law

For green

sin60/sin34=3x10^8/v2

as v2 is final velocity solving

v2=3x10^8xsin34/sin60

Similarly for yellow

v2=3x10^8xsin32/sin60

From here it's obvious green is faster.

If you have any problems with the solution (not the notation), please ask.

 

[ohexploitable]

Yellow is faster because it's refracting at an angle less than green, hence faster. The greater the angle, the slower (greater the change) the light will travel at.

Incase you doubt me or want a source:
Optical Society of America: Exploring the Science of Light - Teachers and Parents: Articles: The Refraction of Light
Search "The greater the change in velocity and wavelength, the greater the change in direction."

That kinda contradicted every you said.

 

[hscishard]

Yellow is faster because it's refracting at an angle less than green, hence faster. The greater the angle, the slower (greater the change) the light will travel at.

Incase you doubt me or want a source:
Optical Society of America: Exploring the Science of Light - Teachers and Parents: Articles: The Refraction of Light
Search "The greater the change in velocity and wavelength, the greater the change in direction."

Dude wtf. I just read it again.

Be more specific. Someone(or just me) would think,"Wait wtf, when light travels from water to air, it makes a big angle. So it travels slower?

 

[lucyc19]

Beams of yellow light and green light are incident onto a rectangular glass slab at 60°. The angles of refraction for these beams are measured at 34° (green) and 32° (yellow). State which colour travels faster in glass. Justify your answer.

I'm confuddled

Hi,
hopefully you have this by now, but imagine a car travelling from road onto sand on the same 60 degree angle. The right wheels hit first and are slowed down, but for a fraction longer, the left wheels are still on the road (concrete or whatever). So, with the left wheels spinning faster, the car turns right. If the green comes in at 34 and the yellow at 32, then the yellow has been refracted more = it has slowed more. Therefore, the green is faster.

The other way to do this is with snell's law. v1 on v2 = sinI on sinr. seeing v1 is the speed of light, you can do 2 equations and will have the answer.

BY THE WAY, I agree with Mirakon.

 

[hscishard]

Bump. Rofl

What's the answer again?

 

[hscishard]

The yellow refractive index is smaller, therefore the change in speed is lesser. Hence yellow is faster.

That is true?

 

[mirakon]

No, those two values are inversely proportional, not proportional. so in fact, yellow is slower.

 

[hscishard]

Lol. Shit book. That was nowhere near your answer.