Two coherent monochromatic point sources $$S_{1}$$ and $$S_{2}$$ of wavelength $$\lambda=600$$ nm are placed symmetrically on either side of the center of the circle as shown. The sources are separated by a distance $$d=1.8$$ mm. This arrangement produces interference fringes visible as alternate bright and dark spots on the circumference of the circle. The angular separation between two consecutive bright spots is $$\triangle\theta$$. Which of the following options is/are correct?