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?
SET -1 In a series LCR circuit, the voltages across an inductor, a capacitor and a resisitor are 30 V, 30V and 60 V respectively. What is the phase difference between the applied voltage and the current in the circuit? Ultraviolet radiations of different frequencies f1 and f2 are incident on two photosensitive materials having … Continue reading CBSE Question Paper 2007
(Collected from Previous Board Question Papers and CBSE Sample Papers andGuess Papers made by experienced teachers) Where does centre of curvature of a spherical mirror lie? Name two important properties of a magnet. How is 1 ohm related to ampere and volt? Draw neat ray diagrams to illustrate the formation of images due to a beam of light incident … Continue reading Commonly asked questions for AISSE (CLASS X CBSE) Physics (Set – 1)