In a Fraunhofer diffraction at a single slit of width 'd' and incident light of wavelength $$5500 \mathop A\limits^o$$, the first minimum is observed at an angle $$30^{\circ}$$. The first secondary maxima is observed at an angle $$\theta$$, equal to

Two monochromatic beams of intensities I and 4 I respectively are superposed to form a steady interference pattern. The maximum and minimum intensities in the pattern are

The path difference between two interfering light waves meeting at a point on the screen is $$\left(\frac{57}{2}\right) \lambda$$. The bond obtained at that point is

In Young's double slit experiment, in an interference pattern, a minimum is observed exactly in front of one slit. The distance between the two coherent sources is '$$\mathrm{d}$$' and '$$\mathrm{D}$$' is the distance between the source and screen. The possible wavelengths used are inversely proportional to