Optics B/C

[chalker]

Sorry to deviate from the discussion, but does anybody have the solutions for the 2011 Nationals Optics test on the test exchange?

Since I created the test, yes I have the solutions. However I have a general policy of not giving out the answer keys to my tests. I release them so they can serve as a learning tool. I believe they are more effective if you have to spend more time to come to an answer and be confident in that answer, than to simply glance at the question and the answer and say 'yep, makes sense'.

That said, I am happy to clarify any confusion there is over specific questions or verify specific answers assuming there is some reason given for there being uncertainty.

[chalker]

The numbers it gives you isn't its angle. I think its the dimensions of the blind spot? 7.5 high and 5.5 wide?

This is the correct approach. The key here is many people assume the blind spot is perfectly circular, thus want to give a single number for field of view. In reality it's ovalish, thus you need 2 numbers to properly characterize it.

[JSGandora]

That's why I very roughly averaged it. So would we get 6.5?

[chalker]

That's why I very roughly averaged it. So would we get 6.5?

I think you need to re-read my previous comment closely. I said exactly the opposite.

[Infinity Flat]

That's why I very roughly averaged it. So would we get 6.5?

Not exactly. The blind spot is somewhat elliptical in shape, so in able to properly describe it you need both dimensions.
If you want the diameter of a circle with equal area to the ellipse, it's about 6.423.

[JSGandora]

Oh, my bad. Then what cngu23 said is correct?

[Infinity Flat]

Oh, my bad. Then what cngu23 said is correct?

It's the dimensions of the Blind spot, but those dimensions are still in degrees.

[JSGandora]

Sorry, I don't understand. Is that a yes or a no? The initial question was

"What is the approximate field of view size of the eye's blind spot?"

and isn't the field of view measured in degrees?

[chalker]

Sorry, I don't understand. Is that a yes or a no? The initial question was

"What is the approximate field of view size of the eye's blind spot?"

and isn't the field of view measured in degrees?

Yes, the field of view should be measured in degrees. The point is it's not circular, it's elliptical. Thus you need to give 2 degree answers to appropriately characterize the field of view: effectively, the 'horizontal' degrees and the 'vertical' degress.

[blue cobra]

Does anyone know of a good source for a class 2 green laser?