[tex]Dane:\\r = 40 \ cm\\n = 1,5\\Szukane:\\f = ?\\\\Rozwiazanie\\\\\frac{1}{f} = (n-1)\cdot\frac{1}{r}\\\\\frac{1}{f} = (1,5-1)\cdot\frac{1}{40 \ cm}\\\\\frac{1}{f} = \frac{1}{2}\cdot\frac{1}{40 \ cm}\\\\\frac{1}{f} = \frac{1}{80 \ cm}\\\\\boxed{f = 80 \ cm}[/tex]
Odp. Ogniskowa tej soczewki f = 80 cm.
