Lens with different refraction index on each side

[JoeyBob]

Homework Statement

see attached

Relevant Equations

1/p+1/q=-2/R

So I am not really familiar with lens questions when there's 2 different refraction indexes. I tried using n1/p+n2/q=-(n2-n1)/R but it doesn't seem to work.

p would be the actual location of the fly and q would be the virtual location, what the fish sees if I am understanding correctly. n1 would be the index of refraction where the fly is and n2 where the virtual image is?

So 1/60+1.3/q=-1.3/64. q=-35.155

So the image is 35.155 cm above the water. But this is wrong, the answer is 60.88 cm

 

[TSny]

n1/p+n2/q=-(n2-n1)/R

So 1/60+1.3/q=-1.3/64

The 1.3 on the right side is not correct.

 

[JoeyBob]

The 1.3 on the right side is not correct.

The rest is correct then?

Shouldn't it be on top according to the formula?

 

[TSny]

The rest is correct.

Shouldn't it be on top according to the formula?

I'm not sure what you are asking here.

 

[JoeyBob]

n1/p+n2/q=-(n2-n1)/R

is this formula incorrect here?

 

[TSny]

The formula looks correct, although I’m not sure what sign conventions you are using for R, etc.

You made a mistake in calculating $n_2-n_1$.

 

[JoeyBob]

The formula looks correct, although I’m not sure what sign conventions you are using for R, etc.

You made a mistake in calculating $n_2-n_1$.

ya I am dumb. 1.3-1 isn't the same as 1.3-0. I get q = -60.88 when I use 0.3, so 60.88 above the water.

Thanks.

 

[TSny]

ya I am dumb.

Not at all. We all make slips like this

1.3-1 isn't the same as 1.3-0. I get q = -60.88 when I use 0.3, so 60.88 above the water.
Thanks.

Looks good.