Central (GMT â 6 hours) Saskatchewan, province of Canada, one of the Prairie Provinces. It is one of only two Canadian provinces without a saltwater coast, and it is the only province whose boundaries are all wholly artificial (i.e., not formed by natural features).
A diffraction grating is a optical material or device that is usually designed to break up white light into the various colors of the visible spectrum.laze angles are used to concentrate a diffraction grating output on a certain band region of the light spectrum. This is done to obtain a maximum resolution in a particular band of light known as the Blaze wavelength.
For a thin double convex lens, refraction acts to focus all parallel rays to a point referred to as the principal focal point. The distance from the lens to that point is the principal focal length f of the lens.For a double concave lens where the rays are diverged, the principal focal length is the distance at which the back-projected rays would come together and it is given a negative sign.he principal focal length of a lens is determined by the index of refraction of the glass, the radii of curvature of the surfaces, and the medium in which the lens resides. It can be calculated from the lens-maker's formula for thin lenses.