Which type of wavefront is formed by a point source emitting uniformly in all directions?

In interference and diffraction, light energy is redistributed. If it reduces in one region (dark fringe), it increases in another region (bright fringe). A. As there is no net gain or loss of energy, these phenomena are consistent with the principle of conservation of energy. B. Diffraction and interference are characteristics exhibited only by light waves. Choose the correct option:

Two waves of intensity I and 4I produce a resultant intensity of 5I in an interference experiment. What is the phase difference between the two waves?