If in a plano-convex lens, the radius of curvature of the convex surface is $10 c m$ and the focal length of the lens is $30 c m$ , then the refractive index of the material fo lens will be

1.5

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1.66

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1.33

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Solution

The correct option is C $1.33$
$(1 / f) = (n - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$
put $R_{2} \to \infty$ for plane surface
and $R_{1} = 10 c m$ with $f = 30 c m$
we get refractive index $n = 4 / 3 = 1.33$
Option c is correct.

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Similar questions

If in a plano-convex lens radius of curvature of convex surface is 10 cm and the focal length of the lens is 30 cm, the refractive index of the material of the lens will be:

If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be

[CPMT 1986; MNR 1988; MP PMT 2002; UPSEAT 2000]

Q. In a plano convex lens the radius of curvature of the convex lens is

10 c m

. If the plane side is polished, then the focal length will be
(Refractive index

= 1.5

)

Q. The radius of curvature of curved surface of a plano-convex lens is

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. The refractive index of the lens material is

1.5

. The focal length of plano-convex lens is (surroundings is air)

Q. The radius of the curvature of the convex surface of a plano-convex lens is

20

cm. If the refractive index of the material of the lens is

1.5

. Its focal length is:

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If in a plano-convex lens, the radius of curvature of the convex surface is 10cm and the focal length of the lens is 30cm, then the refractive index of the material fo lens will be

The correct option is C 1.33(1/f)=(n−1)(1R1−1R2)put R2→∞ for plane surfaceand R1=10cm with f=30cm we get refractive index n=4/3=1.33 Option c is correct.

If in a plano-convex lens, the radius of curvature of the convex surface is $10 c m$ and the focal length of the lens is $30 c m$ , then the refractive index of the material fo lens will be

The correct option is C $1.33$
$(1 / f) = (n - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$
put $R_{2} \to \infty$ for plane surface
and $R_{1} = 10 c m$ with $f = 30 c m$
we get refractive index $n = 4 / 3 = 1.33$
Option c is correct.