Perceived/Actual Object Distance in Water

[SuperSneaky24]

I am a little confused about the actual/perceived distance an object is in water.

I always thought the perceived object looked like this:

where the apparent depth was different than the actual depth, but the lateral distance from the observer is the same.

However today, I encountered a Kaplan PS question that used this:

Where the apparent depth and the actual depth is the same but the lateral distance from the observer is different.

How do I know when to use which?

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[Gauss44]

According to this, it looks closer to the actual surface: http://dev.physicslab.org/Document.aspx?doctype=3&filename=GeometricOptics_RefractionPhenomena.xml

Here's a second source: http://www.physicstutorials.org/home/optics/refraction-of-light/apparent-depth-real-depth

 

[SuperSneaky24]

Yeah so wtf Kaplan. The question btw was:

A penny sits on the bottom of a swimming pool 1m latearlly frm the ledge. An individual standing on the ledge observes the penny to be:

A) less than 1m away from the ledge
B) exactly 1m away from the ledge
C) more than 1m away from the ledge
D) magnified

They said the answer was C but I chose B. Is there anything I'm missing?

 

[1bls2g]

The depth perception is not the same as the distance perception. They're both based on the same refraction, and you are correct about depth, but wrong about applying that to distance.

If you look at the top image, you can see that if you extend the dashed line through the imaginary box and down to the bottom of the pool, the distance of the perceived box would be farther from the ledge than the actual box.

 

[1bls2g]

It's actually kind of a strange question, though, based on the answer choices including "magnified"...It would actually look higher up and farther away/magnified...I think. lol **** Kaplan.

 

[1bls2g]

Oh I actually see how you said you want to know when to use which. In that case, I have no freaking clue. They are both based on the same refraction...Hmm....