The refractive index of a material of a plane-concave lens is 5//3 the radius of curvature is 0.3m. The focal length of the lens in air is

The refractive index of a material of a plane-concave lens is 5//3 the

1.	The refractive index of a material of a plane-concave lens is 5//3 the radius of curvature is 0.3m. The focal length of the lens in air is
Answer» `-0.45m` `-0.6m` `-0.75m` `-1.0m` Solution :(a) LENS MAKER's formual `1/f=(mu-1)[1/(R_(1))-1/(R_(2))]` where `R_(2)=OO,R_(1)=0.3m` `:. 1/f=(5/3-4)(1/0.3-1/(oo))` `implies1/f=2/3xx1/0.3` or `f=0.45m`

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The refractive index of a material of a plane-concave lens is 5//3 the radius of curvature is 0.3m. The focal length of the lens in air is

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