Homework Help: Radius of curvature of partially cut glass surface

1. Aug 15, 2014

desmond iking

1. The problem statement, all variables and given/known data
when the glass is partially cut( as shown in the photo ) , the centre of curvature is inside the denser medium (glass), so the centre of curvature should be lower than point Q in the diagram . am i correct? by saying that the centre of curvature is inside the denser medium , the radius of curvature should be positive ( upload error, so i attached the image directly here ) , but the notes from my book give sample ans which the radius of curvature is negative because the object is concave relative to the refracting surface.

how can the notes spherical surface convex to the less dense medium or C in the denser medium correct?

2. Relevant equations

3. The attempt at a solution

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• IMG_20140816_120915[1].jpg
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2. Aug 16, 2014

Simon Bridge

I don't see a point Q in any of the attachments.

3. Aug 16, 2014

desmond iking

point Q is here. refer to the latest attachment please.

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• IMG_20140816_120813.jpg
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4. Aug 16, 2014

Simon Bridge

Oh OK - the top of the block is 3cm above Q, which is on the table top. It's radius of curvature is 10cm.
Therefore the center of curvature is below the table-top.

If the center of curvature is on the same side as where the light comes from, then it's sign is negative.