What is the correct way to draw this internal reflection

[Syndy]

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The answer is saying the following,

initial reflection + 0 or 1 further reflection only, not at lower surface

must be straight and reach within 1cm of end.
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How come 0 or 1 reflection only ? The length is long to take only one reflection!

I also attached a photo of how I think it should be drawn.

Thank you for your help!

 

[sophiecentaur]

Looking at your drawing, it seems to me that the first reflection is not symmetrical.. Did you draw a Normal and get the angles i and r the same.? Your picture seems to bring the first reflection to hit the lower surface much too soon. I could believe the 'real answer' more than yours. (That third reflection of yours looks even worse.)

 

[Syndy]

Actually this is not my drawing . I found it in the internet but this is exactly the way I have drawn too.

 

[sophiecentaur]

Well, it can't be right if it doesn't follow the laws of reflection, can it?

 

[Syndy]

I agree. It doesn't follow the law of reflection !

 

[sophiecentaur]

So it's wrong. Draw it so it does follow the law and you should get the right answer.

 

[Syndy]

What do you think about the asnwer in the mark scheme?

 

[sophiecentaur]

I can't be bothered to draw it out but it looks OK when I do it 'by eye'. Have you drawn it out carefully and do you disagree with it?