To solve this problem it is necessary to apply the concepts related to the principle of superposition and the equations of destructive and constructive interference.
Constructive interference can be defined as

Where
m= Any integer which represent the number of repetition of spectrum
 = Wavelength
= Wavelength
d = Distance between the slits.
 = Angle between the difraccion paterns and the source of light
= Angle between the difraccion paterns and the source of light
Re-arrange to find the distance between the slits we have,



Therefore the number of lines per millimeter would be given as



Therefore the number of the lines from the grating to the center of the diffraction pattern are 380lines per mm
 
        
             
        
        
        
I believe it is acceleration
        
                    
             
        
        
        
D. They are heterotrophs that digest food internally.
        
             
        
        
        
Answer:
Final speed of the train is 7.5 m/s
Explanation:
It is given that,
Uniform acceleration of the train is, a = 1.5 m/s²
It starts from rest and travels for 5.0 s. We have to find the final velocity of the train. By using first equation of motion as :

Here, train starts from rest so, u = 0
 
  
v = 7.5 m/s
So, the final velocity of the train is 7.5 m/s. Hence, this is the required solution.