The Physics PHYA2 thread! 5th June 2013

Incident substance is the core.

Alright then! sini(critical)=n2/n1. n2 is 1.45 and n1 is 1.55. critical angle is therefore 69.3 deg. So, 1 (criteria) is met and the other isn't. Then, why refraction and not reflection.?

Do you have to show that? And wouldn't it be based on wavelengths?

there you go core (refractive index of 1.47) cladding (refractive index of 1.45) angle of incidence does not exceed critical angle therefore NO T.I.R. if angle of incidence does exceeds critical angle then you DO GET T.I.R. however if angle of incidence does exceeds critical angle but core (refractive index of 1.45) cladding (refractive index of 1.47) then you will get refraction since core is optically less dense than the cladding.

You would just show the screen how you would see it if you were looking at it. Meaning you would just draw a rectangle/square/your favourite shape and show the maxima as either the same width or half the width of the central maxima (depending on whether its double slit or single).

As for indicating the violet colour near to the central maxima, you would just label it saying something like 'the maxima closer to the central maxima have a violet tinge while the maxima further away take on an increasingly darker red tinge'.



Yeah tell me about it! On average, you can drop 9 marks and still walk away with full UMS. Seems like a golden opportunity but I just know I'm going to throw away marks somewhere tomorrow

there you go core (refractive index of 1.47) cladding (refractive index of 1.45) angle of incidence does not exceed critical angle therefore NO T.I.R. if angle of incidence does exceeds critical angle then you DO GET T.I.R. however if angle of incidence does exceeds critical angle but core (refractive index of 1.45) cladding (refractive index of 1.47) then you will get refraction since core is optically less dense than the cladding.

Sorry, you are mistaken there. Cladding has refractive index of 1.45 not 1.47. So, core is more dense than cladding.

Hey, Can anyone help me with January 2013 question 7b(ii), 7(c) and 7(e) ??
thanks

omg lool im giving you an example of when IF​ cladding is greater than core and when core is greater than cladding

does anyone understand wavelets and how the waves passing through a single slit actually manages to interfere with itself to create minimas?

No! All I was saying that why TIR does not occur if incident substance has larger refractive index than the other? Can you answer this? HUH? same question.

wait, I thought each maxima would contain all the colours of the white light spectrum with violet/blue on the inner side closer to the centre and red on the outer side

you seem to suggest that a maxima would contain only one colour (or mainly one colour), or have I misinterpreted you?

No that really isn't what you were saying. Your reasoning alluded to TIR being possible if only a single criteria was met.
Proofs:

Ideally, should the cladding be more refractive or less refractive than the core?

I'm guessing less refractive so TIR occurs?

No that really isn't what you were saying. Your reasoning alluded to TIR being possible if only a single criteria was met.
Proofs:

Ideally, should the cladding be more refractive or less refractive than the core?

I'm guessing less refractive so TIR occurs?

the cladding should have a lower refractive index than the core or TIR will not occur

Alright man. Anyway, I will just have to stick to the rules. Does not matter about the reason why. Thanks for your help.