The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

The radius of curvature of curved surface at a thin planoconvex lens i

1.	The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,
Answer» 5 cm 10 cm 15 cm 20 cm Solution :ACCORDING to len.s maker formula, `(1)/(f)=(n-1)((1)/(R_(1))-(1)/(R_(2)))` `R_(1)=oo:R_(2)=-R` `thereforef=(R)/((n-1))(R=10cm,n=1.5)` `f=(10)/((1.5-1))=20CM`

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The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,

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