Figure shows Fraunhofer's diffraction due to a single slit. If first minima is obtained in the direction shown, then the path difference between ray 1 and ray 3 is
1
2/3
2
2/2
3
λ
4
zero
Figure shows Fraunhofer's diffraction due to a single slit. If first minima is obtained in the direction shown, then the path difference between ray 1 and ray 3 is