The Total solution for NCERT class 6-12
Theimage of a small electric bulb fixed on the wall of a room is to be obtained onthe opposite wall 3 m away by means of a large convex lens. What is the maximumpossible focal length of the lens required for the purpose?
Distance between the object and theimage, d = 3 m
For real images, themaximum focal length is given as:
Hence,for the required purpose, the maximum possible focal length of the convex lensis 0.75 m.