The radii of curvature of both the sides of a convex lens are 15 cm and if the refractive index of the material of the lens is 1.5, then focal length of lens in air is ......... cm.

The radii of curvature of both the sides of a convex lens are 15 cm an

1.	The radii of curvature of both the sides of a convex lens are 15 cm and if the refractive index of the material of the lens is 1.5, then focal length of lens in air is ......... cm.
Answer» 10 15 20 30 Solution :From Lensmaker.s formula, `1/f=(mu-1)(1/R_1-1/R_2)` Here,taking `R_1=15,R_2=-15,mu=1.5,` `THEREFORE 1/f=(1.5-1)((2)/(15))=(0.5xx2)/(15)` `implies f=(15xx10)/(5xx2)`=15 CM

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The radii of curvature of both the sides of a convex lens are 15 cm and if the refractive index of the material of the lens is 1.5, then focal length of lens in air is ......... cm.

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