Calculate the focal length of a biconvex lens in air if the radii of its surfaces are 60 cm and 15 cm. Refractive index of glass = 1.5

Calculate the focal length of a convex lens whose radii of curvature of two surfaces is 10cm and 15cm respectively and its refractive index is 1.5.

(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.)

(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 ?

i. If f = 0.5 m for a glass lens, what is the power of the lens ? ii. The radii of curvature of the faces of a double convex lens are 10cm and 15cm . Its focal length is 12cm. What is the refractive index of glass ? iii. A convec lens has 20 cm focal length in air. what is focal length in water ? (Refractive index of air-water = 1.33, refractive index for air-glass = 1.5)

What is the focal length of double concave lens kept in air with two spherical surfaces of radii R_1 = -30 cm and R_2=60 cm . Take refractive index of lens as n = 1.5.

(i) If f = 0.5 m for a glass lens, what is the power of the lens? (ii) 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 glass? (iii) A convex lens has 20 cm focal length in air. What is focal length in water? (Refractive index of air-water = 1.33, refractive index for air-glass = 1.5.)