Ray Optics and Optical Instruments - Result Question 28

28. A double convex lens has focal length 25cm. The radius of curvature of one of the surfaces is double of the other. Find the radii if the refractive index of the material of the lens is 1.5.

[NEET Odisha 2019]

(a) 50cm,100cm

(b) 100cm,50cm

(c) 25cm,50cm

(d) 18.75cm,37.5cm

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Answer:

Correct Answer: 28. (d)

Solution:

(d) 1f=(μ1)(1R11R2)

125=(1.51)(1R+12R)125=0.5(32R)

2R=37.5cmR=18.75cm



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