8.A luminous object is placed 20cm from surface of a convex mirror and a plane mirror is set so that virtual images forms in two mirror coincide.If plane mirror is at a distance of 12cm from object, then the focal length of convex mirror is ------- Share with your friends Share 13 Neha Gupta answered this According to the fig , object distance for conex mirrro = -20 cmu = -20 cmimage distance = v =4 cm focal length is given by:1f=1v+1u1f = 14+1-201f=5-120f = 204 = 5 cm 18 View Full Answer
