Posted by **Sarah N H** on Saturday, January 16, 2010 at 9:49am.

Sam is sitting in her fishing boat watching a trout swim below the surface. She guesses the apparent depth of the trout at 2.0m. She estimates that her eyes are about 1.0 m above the water's surface, and that the angle at which she's observing the trout is 45 degrees.

b) Calculate the actual depth of the trout

I have calcualted the angle of incidence to be 32 degrees, but still have no idea how to figure out the depth. I have been trying for 2 hours since last night. I don't know what trig to use on this. Can you help please?

- physics -
**bobpursley**, Saturday, January 16, 2010 at 10:30am
http://www.saburchill.com/physics/chapters3/0004.html

So Real depth= apparent depth/ tan i

check my thinking.

- physics -
**drwls**, Saturday, January 16, 2010 at 10:30am
The formula that you need is derived and presented here:

http://www.physicstutorials.org/index.php/home/optics/refraction-of-light/apparent-depth-real-depth

The object will appear at a shallower depth equal to the real depth divided by the refractive index of water.

- physics -
**Sarah N H**, Saturday, January 16, 2010 at 11:15am
Bob: your website, when I rearrange the formula, would be real depth = X/tani...What is the 'x" in my problem?

DRWLS: I am solving for the actual depth, the apparent depth is given...do I still use your same formula?

Thankyou both.

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