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
- 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
(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 parallel to the principal axis of a (i) concave mirror, (ii) convex mirror in each case. Why is a series arrangement not used for connecting domestic electrical appliances in a circuit? Out of 60 W and 40 W lamps, which one has a higher electrical resistance when in use? Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed.(a) at F (b) Between F and O What is meant by the term, ‘magnetic field’? Why does a compass needle show deflection when brought near a bar magnet? Two lamps, one rated 60W at 220 V and the other 40W at 220 V, are connected in parallel to the electric supply at 220V.(a) Draw a circuit diagram to show the connections.
(b)Calculate the current drawn from the electric supply.
(c)Calculate the total energy