the second course of light

angle aperture appear axis beam blue bright Calculate called caused centre colour concave consider consists converging curvature curve dark Describe determinations diameter diffraction direction distance effect equal equation experiment Explain eye lens eyepiece face falls field Find focal length focus formed fringes given gives glass grating green hence illumination incident increased intensity interference known lamp lenses light lines luminous magnifying power means measured method microscope mirror moved Newton's normal object observed obtained occur optical parallel passing path perpendicular photographic placed plane plate polarised position principle prism produced pupil radiation radius rays reflected refractive index represents respectively result rings rotation screen seen sensitive shown side slit sodium spectral spectrum surface telescope theory thickness thin transmitted velocity vibrations vision wave-length waves white light yellow zones