The Diffraction Grating

Resolving Power of the Diffraction Grating

For two nearly equal wavelengths λ1 and λ2 between

which a diffraction grating can just barely distinguish, the resolving power R of the grating is defined as:

(4.10)

(4.11)

Diffraction of X-Rays by Crystals

(a) A Laue pattern of a single crystal of the mineral beryl (beryllium aluminum silicate). Each dot represents a point of constructive interference. (b) A Laue pattern of the enzyme Rubisco, produced with a wide-band x-ray spectrum. This enzyme is present in plants and takes part in the process of photosynthesis. The Laue pattern is used to determine the crystal structure of Rubisco.

Diffraction of X-Rays by Crystals

Bragg’s law

(4.12)

Polarization of Light Waves

The direction of polarization of each individual wave is defined to be the direction in which the electric field is

vibrating.

unpolarized light

linearly polarized

Polarization of Light Waves

Polarization by Selective Absorption

(4.13)

Malus’s law

Polarization of Light Waves

The intensity of light transmitted through two polarizers depends on the relative orientation of their transmission axes. (a) The transmitted light has maximum intensity when the transmission axes are aligned with each other. (b) The transmitted light has lesser intensity when the transmission axes are at an angle of 45° with each other. (c) The transmitted light intensity is a minimum when the transmission axes are perpendicular