Home
Class 12
PHYSICS
(i) If f = + 0.5 m, what is the power of...

(i) If `f = + 0.5 m`, what is the power of the lens ?
(ii) The radii of curvature of the faces of a double convex lens are `9 cm and 15 cm`. Its focal length is `12 cm`. What is the refractive index of glass ?

Text Solution

Verified by Experts

(a) `P = (1)/(f(m)) = (1)/(0.5) = +2D " "` (b) `(1)/(f) = (mu-1)((1)/(R_(1)) - (1)/(R_(2))) implies (1)/(12) = (mu-1)((1)/(10) - (1)/(-15)) implies mu=1.5`
(c) `(1)/(f) = (mu-1) ((1)/(R_(1)) - (1)/(R_(2))) "so" (1)/(f) alpha (mu-1), (f_(w))/(f_(a))= ((mu_(l)-1))/((._wmu_(l) -1)) implies f_(w) = ((1.5-1))/(((1.5)/(1.33) - 1))xx 20 = 78.2 "cm"`
Promotional Banner

Topper's Solved these Questions

  • GEOMETRICAL OPTICS

    ALLEN |Exercise SOME WORKED OUT EXAMPLES|84 Videos

  • GEOMETRICAL OPTICS

    ALLEN |Exercise EXERCISE -01|65 Videos

  • CURRENT ELECTRICITY

    ALLEN |Exercise EX.II|66 Videos

  • GRAVITATION

    ALLEN |Exercise EXERCISE 4|9 Videos

Similar Questions

Explore conceptually related problems

(i) If f = 0.5 m for a glass lens, what is the power of the lens? (ii) The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. Its focal length is 12 cm. What is the refractive index of glass? (iii) A convex lens has 20 cm focal length in air. What is focal length in water? (Refractive index of air-water = 1.33, refractive index for air-glass = 1.5.)

(i) If f =- 0.2 m for a glass lens, what is the power ofthe lens? (ii) The radii ofcurvature ofthe faces of a double convex lens are 15 cm and 12 cm. Its focal length is 15 cm. What is the refractive index of glass ? (iii) Refractive index and radii of curvature oftwo equal plana-convex lens are 1.5 and 20 cm respectively. They are placed in a vessel such that their convex surfaces are in contact at centre and oil ofrefractive index 1.7 is filled in them, then what will be the focal length of combination ?

Radius of curvature of plano-convex lens is 10 cm. If its focal length is 30 cm, then its refractive index will be .......

If radius of curvature of curved surface of plano-convex lens of refractive index 1.5 is 60 cm, then its focal length is ...... cm.

The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it will

The refractive indices of water and glass are 1.2 and 1.5 respectively. What will be the refractive index of glass with respect to water ?

A plano-convex lens of radius of curvature 30 cm and refractive index 1.5 is kept in air. Find its focal length (in cm).

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.

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.