Answer
(a) $2.58cm$
(b) $2.38cm$
Work Step by Step
(a) We can find the focal length of the eye as
$f=(\frac{1}{d_i}-\frac{1}{d_\circ})^{-1}$
We plug in the known values to obtain:
$f=(\frac{1}{2.60cm}-\frac{1}{285cm})^{-1}$
$f=2.58cm$
(b) As $f=(\frac{1}{d_i}-\frac{1}{d_\circ})^{-1}$
We plug in the known values to obtain:
$f=(\frac{1}{2.60cm}-\frac{1}{28.5cm})^{-1}$
$f=2.38cm$
