tu cong thuc giua chiet suat; ban kinh mat loi va tieu cu co:$\frac{1}{f2}=(n2-1)\frac{2}{R}$
$<=> R=2(n2-1)f2=2(1.51-1)100=102mm$
cung cong thuc do ap dung cho 2 anh sang do va lam co
$f1=\frac{R}{2(n1-1)}=\frac{100}{2(1.5076-1)}\approx 98.503mm$
$f3=\frac{R}{2(n3-1)}=\frac{100}{2(1.51565-1)}\approx 96.965mm$
khoang cach giua 2 tieu diem cua thau kinh vs anh sang do va lam la:
$l=f1-f2=1.538mm$