A concave mirror of radius R is kept on a horizontal table. Water (refractive index =mu.) is poured into it up to a height h. Where should an object be placed so that its image is formed on itself ?

Explanation

Let the object be placed at a height 'x' above the surface of water. The apparent position of the object with respect to the mirror should be at the center of curvature so that the image is formed at the same position.
Since `("Real depth")/("Apparent depth")=(1)/(mu)`
(with respect to the mirror), therefore
`(x)/(R-h)=(1)/(mu)`
or `x=(R-h)/(mu)`