An object 20 cm from a spherical mirror gives rise to a virtual image 15 cm behind the mirror. The type of the mirror and its focal length is (a) concave, 8.5 cm (b) convex, 30 cm (c) concave, 60 cm (d) convex, 60 cm. Share with your friends Share 1 Rohit Babu answered this Dear Student,Given,u=-20cm,v=+15cm(Image is formed behind the mirror.)1f=1u+1v⇒1f=-120+115=-3+460=+160⇒f=60cmAs the focal length is positive,the mirror used is convex.Answer : (d)convex,60cmRegards. 0 View Full Answer