A person got his eyes tested by an optician. The prescription for the spectacle lenses to be made reads :
Left eye : +2.50 D
Right eye : +2.00 D
(a) State whether these lenses are thicker in the middle or at the edges.
(b) Which lens bends the light rays more strongly?
(c) State whether these spectacle lenses will converge light rays or diverge light rays.

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Solution

(a) These lenses are thicker in the middle because they are convex lens.
(b) Power is inversely proportional to focal length; therefore, shorter focal length will mean strong bending. Hence, lens for left eye will bend light rays more strongly.
(c) These spectacles will converge light rays because convex lens has positive power.

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Similar questions

A person got his eyes tested by an optician. The prescription for the spectacle lenses to be made reads : Left eye : + 2.50 D Right eye : + 2.00 D (a) State whether these lenses are thicker in the middle or at the edges. (b) Which lens bends the light rays more strongly ? (c) State whether these spectacle lenses will converge light rays or diverge light rays.

Q. The optical prescription of a pair of spectacle is - Right eye : - 3.5 D, Left eye : - 4.00 D
i) Name the defect of the eye
ii) Are these lenses thinner at the middle or at the edges?
iii) Which lens has a greater focal length?

Q. State whether true or false :

The degree of convergence of divergence of light rays achieved by a lens is expressed in terms of its power.

Q. The ability of a lens to converge or diverge light rays depends on :

Why concave lens diverge and convex lens converge light rays?

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