A concave or convex lens is given such that radii of curvature are same. If refractive index of glass is 1.5, then its focal length = ...... where R = radius of curvature.

A concave or convex lens is given such that radii of curvature are sam

1.	A concave or convex lens is given such that radii of curvature are same. If refractive index of glass is 1.5, then its focal length = ...... where R = radius of curvature.
Answer» R `R/2` 2R `1/4R` SOLUTION : `1/f=(n-1)(1/R_1-1/R_2)` `=(1.5-2)2/R=1/R` (convex) `thereforef=R` `1/f=(n-1)(-1/R-1/R)` (CONCAVE) `=-(1.5-1)2/R=-1/R` `THEREFORE f=-R``therefore`f=R(value)

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A concave or convex lens is given such that radii of curvature are same. If refractive index of glass is 1.5, then its focal length = ...... where R = radius of curvature.

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