Figure (18-Q3) shows three transparent media of refractive indices μ1, μ2 and μ3. A point object O is placed in the medium μ2. If the entire medium on the right of the spherical surface has refractive index μ1, the image forms at O’. If this entire medium has refractive index μ3, the image forms at O’’. In the situation shown,

There are two different materials present on the right. Hence no of images formed will also be two. So, O’ and O” both are images.