positive lens meaning in Hindi

Examples

1. Of thin positive lenses with n = 1.5, four are necessary to correct spherical aberration of the third order.
2. In science textbooks, positive lenses are usually diagrammed as convex on both sides; negative lenses are usually diagrammed as concave on both sides.
3. With such a known positive lens, you can stack a weaker negative ( nearsighted correction ) lens next to it and from the combined focal length calculate the diopters of the negative lens.
4. Strictly speaking, the Fraunhofer approximation only applies when the diffracted pattern is viewed at infinity, but in practice it can be applied in the far field, and also in the focal plane of a positive lens.
5. If there is refraction at a collective spherical surface, or through a thin positive lens, O'2 will lie in front of O'1 so long as the angle u2 is greater than u1 ( " under correction " ); and conversely with a dispersive surface or lenses ( " over correction " ).
6. In most cases, two thin lenses are combined, one of which has just so strong a positive aberration ( " under-correction, " vide supra ) as the other a negative; the first must be a positive lens and the second a negative lens; the powers, however : may differ, so that the desired effect of the lens is maintained.