We know that
Absolute Pressure by definition is is zero-referenced against perfect vacuum.
Gauge Pressure is zero-referenced against ambient atmospheric pressure.
Therefore, Absolute Pressure is equal to gauge pressure
In the given problem we have
Absolute pressure and Gauge pressure is
As such outside pressure acting on the window of submarine while at a depth of
Inside pressure is maintained at sea level pressure
Net inward pressure acting on the window
We know that Pressure of
Inserting above values we get
Force acting on the window