Fresnel half period zones are used to describe the contribution of different portions of a wavefront to the intensity at a point in the wave’s path. Each successive zone contributes an equal phase shift but alternates in sign, effectively contributing to the constructive and destructive interference pattern:
- (A) True, as the amplitude of the disturbance from each zone is a function of its area.
- (B) True, as each zone’s radius increases with the square root of its order number.
- (C) True, the area and thus the impact of each zone varies with wavelength, affecting how the wavefront constructs or destructs at a point.
- (D) True, The radii of half period zones are directly proportional to the square root of the wavelength of the light.
In the diagram given below, there are three lenses formed. Considering negligible thickness of each of them as compared to \( R_1 \) and \( R_2 \), i.e., the radii of curvature for upper and lower surfaces of the glass lens, the power of the combination is: