Answer:
shrinks with all the fringes getting narrower
Explanation:
As the light passes through the slit, the diffraction pattern shrinks, as the waves have more opening to penetrate, and the fringes becomes more narrow as a result of that, The opposite happens as the conditions are reversed.
 
        
             
        
        
        
Answer:29.627 m
Explanation:
Given
Initial velocity of life preserver(u) is 1.6 m/s
it takes 2.3 s to reach the water 
using equation of motion
v=u+at

v=24.163 m/s
Let s be the height of life preserver



s=29.627 m
 
        
             
        
        
        
The ball can't reach the speed of 20 m/s in two seconds, unless you THROW it down from the window with a little bit of initial speed. If you just drop it, then the highest speed it can have after two seconds is 19.6 m/s .
If an object starts from rest and its speed after 2 seconds is 20 m/s, then its acceleration is 20/2 = 10 m/s^2 .
(Gravity on Earth is only 9.8 m/s^2.)