Initial difference in height = (150–100) m=50 m
Distance travelled by first body in 2 s=h1=0+12g(2)2=2g
Distance travelled by another body in 2 s=h2=0+12g(2)2=2g
After 2 s, height at which the first body will be = h1=150−2g
After 2 s, height at which the second body will be = h2=100−2g
Thus, after 2 s, difference in height =150−2g−(100−2g)
=50 m = initial difference in height.
Thus, difference in height does not vary with time.