Question

an object is placed in front of a screen and a convex lens is placed such that the size of the image formed is 9 cm . then the lens is shifted through a distance of 20cm the size of the image becomes 1 cm . find the focal length and the size of the image​

Answer 1

Explanation:

An object is placed in front of a screen and a convex lens is placed at a position such that the size of the image formed is 9cm. when the lens is shifted through a distance of 20 cm, the size of the image becomes 1 cm. The focal length of the lens and the size of the object are respectively. A. 7.5 cm and 3.5 cm B. 7.5 cm and 4.5 cm C. 6 cm and 3 cm D. 7.5 cm and 3 cmRead more on Sarthaks.com - https://www.sarthaks.com/951441/object-placed-front-screen-convex-lens-placed-position-such-that-the-size-the-image-formed