Locate the image of the point object O in the situtaion shown. The point C denotes the centre of curvature of the separating surface.

Explanation

Here u=-15cm, R=30cm, `mu_1=1 and mu_2=1.5`. We have `
`mu_2/v-mu_1/u=(mu_2-mu_1)/R`
`or, 1.5/v-1.0/(-15cm=(1.5-1)/(30cm)`
`or `(1.5/c=0.5/(30cm)-1/(15cm))`
`v=-30`
The image is formed 30 cm left to the spherical surface and is virtual.