A sphere of radius R made of material of refractive index `mu_(2)` is placed in a medium of refractive index `mu_(1)`. Where would an object be placed so that a real image is formed at equidistant fromk the sphere? ltbgt

Explanation

Let the object be placed at a distance x from the pole ` P_(1)` of the sphere. If a real image is to be formed at equidistant form the sphere, then the rays must pass symmetrical through the sphere, as shown in the figure is question.
Applying the equation at the first surface, we get
`(mu_(2))/(+oo)-(mu_(1))/(-x)=(mu_(2)-mu_(1))/(+R)`
or `x=((mu_(1))/(mu_(2)-mu_(1)))R`