Answer
$11.7mm$
Work Step by Step
We know that
$M=\frac{N}{f}$
We plug in the known values to obtain:
$M=\frac{25.0cm}{10.1cm}=2.48$
Now we can find the apparent length as
$apparent \space length=M\times actual \space length$
$apparent \space length=2.48\times 4.73=11.7mm$
