AP Physics Help Please....

Test Preparation
1

<p>There are two problems I have been trying to do but I don't know if I'm right or not:</p>

<p>Two converging lenses with focal lengths of 15 cm and 25 cm are placed 18 cm apart. An object is located 8 cm beyond the lens of 15cm focal length. Where, relative to the 25cm lens, is the final image located?</p>

<p>I get .887 cm</p>

<p>Two stars, each located 580 light years from earth, are 4.4 light years apart. What is the smallest diameter which could resolve them using 550 nm light?</p>

<p>And my number comes out 8.845 x 10^-5 which doesn't seem logical to me.</p>

<p>Any help would be appreciated. Thanks.</p>

2

<p>bump... any help is appreciated</p>

3

<p>Dude…if you are still wondering or for future question seekers</p>

<p>Use Rayleigh’s criterion.θ= 1.22λ/D
Where s ( distance)= θH
Combine formulas algebraicly
S= ( 1.22λ/D)H
Substitute
S= 1.22 (630x10^-9/2.4) 580
Result is s= 1.857e-4.</p>

4

<p>I bet he is still wondering about that problem 7 years later.</p>