Two thin lenses of focal lengths f1=20cm and f2=60cm are placed in contact. find the focal length f3 of the combined lenses. find also the focal length f of a third lens placed in contact with these two that would result in overall focal length f11=-40cm. (Asked Young) Incoming search terms:class 9 science sample paper for [...]
Deviation is the change in direction of the ray while passing through the lens. The middle portion of the lens is comparatively flat and there is a point on the principal axis and inside the sphere through which all the undeviated rays pass. “Undeviated” doesn’t mean that there is no refraction. When we say that … Continue reading Why the ray of light passing through optical center of a lens passes undeviated while when it passes through other points on the interface of the lens, it gets refracted?