The answer is; Irregular.
False theyre called plate boundries
C^2=a^2+b^2
c^2=45^2+45^2
c^2=4050
c=63.64
c=64
The answer is D.
Explanation:
It is given that,
Wavelength of monochromatic light, 
Slits separation, 
(a) We need to find the angle corresponding to the first bright fringe. For bright fringe the equation is given as :
, n = 1



(b) We need to find the angle corresponding to the second dark fringe, n = 1
So, 




Hence, this is the required solution.