(ii) The radii of curvature of the faces of a double convex lens are 10 cm and 15cm. Its focal length is 12 cm. What is the refractive index of glass ?
(Refractive index of air-water = 1.33. Refractive index for ar - glass = 1.5.)

The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. If focal length is 12 cm. What is the refractive index of glass?

The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm, Its focal length is 12 cm. What is the refractive index of the glass ?

The radii of curvature of the faces of a double convex lens are 20 cm and 30 cm. Its focal length is 24 cm. What is the refractive index of the glass?

The radii of curvature of the faces of a double convex lens are 20 cm and 20 cm. Its focal length is also 20 cm. What is the refractive index of the glass?

(i) If f =- 0.2 m for a glass lens, what is the power ofthe lens? (ii) The radii ofcurvature ofthe faces of a double convex lens are 15 cm and 12 cm. Its focal length is 15 cm. What is the refractive index of glass ? (iii) Refractive index and radii of curvature oftwo equal plana-convex lens are 1.5 and 20 cm respectively. They are placed in a vessel such that their convex surfaces are in contact at centre and oil ofrefractive index 1.7 is filled in them, then what will be the focal length of combination ?