Refraction Question (1 Viewer)

[MATHmaster]

Hey Guys I need your advice for this MC question on 'the world communicates' from my assessment last term

Here is the question?



What is the correct answer to this question?
I got D but many of the class got C which was incorrect... How do I prove the teacher wrong because she still thinks it's C?

Also the image shows the second ray of light with the arrow pointing due east - it should point in the direction of the light ray... I used paint so yeah

 

[RishBonjour]

How do you know C is incorrect if you don't have the correct answers?

 

[Dan895]

I think its C, because the light bent and therefore refraction occured. In W and X I don't think there is refraction because the light does not bend and It is impossible to tell if refraction occured. Whats your reasoning for D?

 

[MATHmaster]

That's why I'm asking

 

[MATHmaster]

But isn't refraction the change in velocity from one medium to another?

 

[deswa1]

No. The definition of refraction is a change in direction due to a change in its velocity.

 

[MATHmaster]

In the Dotpoint Prelim Physics Book it has the exact same question but it supports my answer:

Refraction is the change in velocity that occurs when a wave passes from one medium to another/
Refraction occurs whenever a wave passes from one medium to another - the angle of incidence of the wave is irrelevant

 

[deswa1]

Yes I know. This is where it gets tricky because different sources have different definitions. In the real world though, I think a change in direction is neccessary. Note http://en.wikipedia.org/wiki/Refraction

Regardless though, your teacher might give you the mark if you show her the book with that definition. Or they might mark both correct.

 

[RishBonjour]

C looks good to me.

 

[Peeik]

No. The definition of refraction is a change in direction due to a change in its velocity.

No. You must include a change in medium in that definition otherwise your definition can mean many other things. The answer should be C.

 

[Deliriously]

I believe if the light ray just passes directly (at 90 degrees) through the medium, it is just transmitted whereas a change in direction would result in refraction.

 

[Kimyia]

I understood refraction to be the bending of light as it changes speed upon entering a medium with a different optical density
i.e. the medium changes, the speed changes, the angle changes.

 

[Dan895]

In the Dotpoint Prelim Physics Book it has the exact same question but it supports my answer:

Refraction is the change in velocity that occurs when a wave passes from one medium to another/
Refraction occurs whenever a wave passes from one medium to another - the angle of incidence of the wave is irrelevant

But if the wave passes through the barrier unbent and their is no information that the wave slowed down then it would be wrong to assume that it slowed down.

So it makes C the correct answer.

 

[qwerty44]

 

[OH1995]

What causes the light to bend is the change in speed, therefore if it maintains the same line in a prism, it hasn't changed speed. Ergo, it has not refracted. C

 

[RealiseNothing]

It's definately C, if the light doesn't bend, it hasn't changed it's velocity.

 

[RealiseNothing]

In the Dotpoint Prelim Physics Book it has the exact same question but it supports my answer:

Refraction is the change in velocity that occurs when a wave passes from one medium to another/
Refraction occurs whenever a wave passes from one medium to another - the angle of incidence of the wave is irrelevant

I think they mean the angle of incidence is irrelevant as in the size, ie. doesn't matter whther it's 30 or 60 degrees, it still refracts.

However if there is no angle of incidence, then it hasn't refracted.

 

[RMKD123]

The answer is C. I had this exact same question in one a past paper my teacher gave me for physics.

 

[barbernator]

What causes the light to bend is the change in speed, therefore if it maintains the same line in a prism, it hasn't changed speed. Ergo, it has not refracted. C

Watch out with this, it does change speed when entering the medium perpendicular to the surface.