1
$\begingroup$

We have a double convex lens with optical power $D = 10$, $f\# = 2$, $n = 1.5$, and $r_1 = -r_2$. What is the minimum thickness of this lens?

I have a solution which is a bit convoluted, so I wonder if I am missing anything that would make it simpler.

From $D$, we have $f = 0.1$.

From $f\#$ and $f$, we have the diameter of the lens equaling $0.05$.

With LME, and $f$ and $n$, we have radius of curvature equaling $0.1$.

The only way I can think of getting thickness is from circular segment.

And solving for the sagitta, because we have the chord length (diameter of lens) and the radius of curvature. And the answer would be two times the sagitta.

This is my solution. I don't think we learned this in class. Is there a simpler way?

$\endgroup$

closed as off-topic by John Rennie, sammy gerbil, Kyle Kanos, Yashas, Jon Custer Dec 21 '17 at 8:45

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – John Rennie, sammy gerbil, Kyle Kanos, Yashas, Jon Custer
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ I asked a friend how he solved it and he did the same thing. Go figure. I guess this way was correct $\endgroup$ – David Dec 21 '17 at 8:25