Double slit diffraction ripple

[Arget]

1. 
   Consider diffraction in a ripple tank from two narrow slits. Answer true (T) or false (F) for each of the following statements. E.g., if the first statement is true and the rest false, enter TFFF. You have 6 tries.
   
   1. If the frequency of the wave source is halved, then the angle between the zeroth and first order fringes is doubled.
      
   2. If the frequency of the source and the space between the slits are both halved, then the angle between the zeroth and first order fringes stays the same.
      
   3. If the frequency of the wave source is doubled, then the phase speed of the waves doubles.
      
   4. If the distance between the slits is doubled, then the angle between the zeroth and first order fringes is doubled.

The attempt at a solution

TFTT
FFTT

 

[mfb]

How did you get those answers?

 

[Arget]

How did you get those answers?

I used the equation dsin(theta) = velocity / frequency

 

[mfb]

As some of your answers are incorrect, a description for every answer could be useful.

The phase velocity is not covered by that equation.