The correct answer is refraction.
        
             
        
        
        
To solve this problem we will apply the concepts related to the double slit-experiment. For which we will relate the distance between the Slits and the Diffraction Angle with the order of the bright fringe and the wavelength, this is mathematically given as,

Here,
d = Distance between Slits 
m = Order of the fringes
 = Wavelength
 = Wavelength
 =
 = 

Rearranging to find the angle,




Therefore the angle that the fourth order bright fringe occur for this specific wavelenth of light occur is 32.19°
 
        
             
        
        
        
Answer:
The final velocity of the wooden block is equal to 
Explanation:
Given that mass of bullet =  
 
                 Mass of wood = 
                Initial velocity of bullet = 
               Final velocity of bullet = 
                Initial velocity of wood = o
                Final velocity of wood = ![v_{w]](https://tex.z-dn.net/?f=v_%7Bw%5D)
    Here momentum is conserved so initial momentum = final momentum 
              .
 .
     Upon substituting these values in above equation , we get
          .
.
 
        
             
        
        
        
A decrease in mass will decrease an objects weight because 
weight = mass x gravitational constant