Concept:
For a freely falling body released from rest:
\[
s=\frac{1}{2}gt^2
\]
Step 1: Total height of tower is \(H\), and total time taken is \(T\).
\[
H=\frac{1}{2}gT^2
\]
Step 2: Distance fallen in time \(T/2\) is:
\[
s=\frac{1}{2}g\left(\frac{T}{2}\right)^2
\]
\[
s=\frac{1}{2}g\frac{T^2}{4}
\]
\[
s=\frac{1}{4}\left(\frac{1}{2}gT^2\right)
\]
\[
s=\frac{H}{4}
\]
Step 3: This is the distance fallen from the top.
Step 4: Height from the ground at that instant is:
\[
H-\frac{H}{4}
\]
\[
=\frac{3H}{4}
\]
\[
\boxed{\frac{3H}{4}}
\]