Answer
$3.61cm$
Work Step by Step
We can find the required height as follows:
$H=W\sqrt{\frac{n_{water}^2-n_{air}^2}{4n_{air}^2-n_{water}^2}}$
We plug in the known values to obtain:
$H=(6.2cm)\sqrt{\frac{(1.33)^2-(1.00)^2}{4(1.00)^2-(1.33)^2}}$
This simplifies to:
$H=3.61cm$
