amplitude angle angular atoms beam biprism bright fringe Calculate called central maximum chromatic constant convex crystal dark ring diffraction grating direction dispersive power displacement distance double-slit experiment electromagnetic electron equation Example eyepiece focal length Fraunhofer diffraction frequency fringe width given harmonic incident inertial frames intensity kinetic energy laser lens system lenses light of wavelength longitudinal waves mass mean position medium Michelson interferometer microscope minima minimum mirror momentum motion moving Newton's rings Nicol prism O-ray observed obtained optical fibre optical rotation oscillations parallel particle path difference perpendicular phase difference photon plane polarized light population inversion potential energy principal maxima prism propagation refractive index relative relativistic resolving power rotation screen shown in Figure slit Solution spectral lines speed of light spherical aberration stimulated emission surface thickness transmitted transverse waves ultrasonic waves unpolarized velocity vibration wavefront wavelength wavelength of light