In a Fresnel biprism experiment, the two positions of lens give separation between the slits as 16 cm and 9 cm, respectively. What is the actual distance of separation?
Fresnel used a biprism to obtain two coherent sources for producing interference fringes in the laboratory. It consists of two acute angled prisms with their bases in contact. In actual practice, the biprism is constructed as a single prisms of obtuse angle of about 179$^{\circ}$ and the remaining two acute angles are 30' each. In bi prism, the virtual images act as two coherent superimposed and interference fringes are formed in overlapping region AB on a screen placed at 0.
In order to measure the distanced between the virtual sources $S_1$ and $S_2$ , Glazebrook gave a method, known as magnification method due to Glazebrook. If $d_1$ and $d_2$ are distance between real images of $S_1$ and $S_2$, then $d = \sqrt{d_1 d_2}$ Given $d_1 = 16 \, cm, \, \, d_2 = 9 \, cm$ $\therefore d = \sqrt{16 \times 9} = 12 \, cm$
Wave optics are also known as Physical optics which deal with the study of various phenomena such as polarization, interference, diffraction, and other occurrences where ray approximation of geometric optics cannot be done. Thus, the section of optics that deals with the behavior of light and its wave characteristics is known to be wave optics.
In wave optics, the approximation is carried out by utilizing ray optics for the estimation of the field on a surface. Further, it includes integrating a ray-estimated field over a mirror, lens, or aperture for the calculation of the transmitted or scattered field.
Wave optics stands as a witness to a famous standoff between two great scientific communities who devoted their lives to understanding the nature of light. Overall, one supports the particle nature of light; the other supports the wave nature.
Sir Isaac Newton stood as a pre-eminent figure that supported the voice of particle nature of light, he proposed a corpuscular theory which states that “light consists of extremely light and tiny particles, called corpuscles which travel with very high speeds from the source of light to create a sensation of vision by reflecting on the retina of the eye”.
