Physics halp! (1 Viewer)

[BloomyLove]

*bangs head against wall*

I'm Screwed.

 

[harhar]

lol halp

 

[mirakon]

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. I think.

 

[hscishard]

It would be more accurate to put the velocity as x.
But yea.

 

[mirakon]

It would be more accurate to put the velocity as x.
But yea.

Not necessarily as velocity is denoted by a 'v'. Mathematically x usually is the term for displacement in 4 unit and x (dot over the top) is velocity. Although x can be used as a variable, it doesn't really matter as long as you don't confuse it with anything else. In this case I was using x for multiplication, so it would have been confusing.

 

[hscishard]

No I'm saying that you assumed that v1 has a velocity of 3 x 10^8. It's really close to this but it isn't unfortunately.

But it is correct. Just saying you shouldn't just write 3 x 10^7

 

[mirakon]

No I'm saying that you assumed that v1 has a velocity of 3 x 10^8. It's really close to this but it isn't unfortunately.

But it is correct. Just saying you shouldn't just write 3 x 10^7

oh whoops, I misinterpreted what you sayed.

However, once again in the HSC syllabus it is enough to assume this approximation of the speed of light: 3x10^8 m/s. Like you assume acceleration due to gravity is 9.8m/s^2. It's a standard. The HSC tests your grasp of the theoretical concepts not how well you memorise numbers.

 

[muzeikchun852]

isnt the change of colour is the change of frequency instead of wavelength?

 

[muzeikchun852]

and this question is from prelim dot point, i did it but i forgot the answer.

 

[ohexploitable]

isnt the change of colour is the change of frequency instead of wavelength?

 

[muzeikchun852]

but as wat i throught is that when a light ray refracts, its wavelength changes, but frequency stays the same. since colour is determined by frequency, there is no colour change during refraction. but this only apply to normal light.

 

[ohexploitable]

lol, there was no mention of a colour change.

 

[hscishard]

What's that last symbol that looks like infinity?

 

[muzeikchun852]

lol, there was no mention of a colour change.

but the light colour is difference, therefore the frequency is difference as well and no change in wavelength as most of the previous posts said the opposite.

 

[ohexploitable]

What's that last symbol that looks like infinity?

Proportionality symbol, i.e. frequency is inversely proportional to wavelength, as frequency increases wavelength decreases and vice versa.

 

[ohexploitable]

but the light colour is difference, therefore the frequency is difference as well.

Yes, the colours have different frequencies.

 

[hscishard]

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

Never seen that symbol before.

 

[muzeikchun852]

In a vacuum, the frequencies and wavelengths of every single type of EMR is like perfect and when multiplied they equal 3x10⁸.

But... when the EMR goes through a medium, it changes. Frequency remains constant, but wavelength changes.

Like in my hypothetical world where the speed of light in a vacuum is 6 m/s...

2 * 3 = 6
3 * 2 = 6

But... when you modify wavelength and keep frequency constant...

2 * (3 - 1) = 4
3 * (2 - 1) = 3

Kablamo! The speeds of the EMR changes!

and wats this?

 

[ohexploitable]

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

Never seen that symbol before.

You haven't done inverse square law?

 

[ohexploitable]

and wats this?

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