JEE Main 10 Apr 2019 Paper 1 Solved Paper

One Plano-convex and one plane of-concave lens of same radius of Curvature ‘R’ but of different materials are joined side by side as shown in the figure . If refractive index of the material of 1 is µ1 and that of 2 is µ2 ,then the focal length of the combination is