Light - Reflection and Refraction Q36(a) — Class 10 Physics Solution

Physics-10th Light - Reflection and Refraction CBSE Board 2025 Hard

(i)The power of a lens 'X' is $- 2.5$ D. Name the lens and determine its focal length in cm. For which eye defect of vision will an optician prescribe this type of lens as a corrective lens ?
(ii)"The value of magnification $m$ for a lens is $- 2$ ." Using new Cartesian Sign Convention and considering that an object is placed at a distance of $20$ cm from the optical centre of this lens, state : (I) the nature of the image formed; (II) size of the image compared to the size of the object; (III) position of the image, and (IV) sign of the height of the image.
(iii)The numerical values of the focal lengths of two lenses A and B are $10$ cm and $20$ cm respectively. Which one of the two will show higher degree of convergence/divergence ? Give reason to justify your answer.

🔒 Step-by-step solution

(i) The power of a lens 'X' is -2.5 D. Name the lens and determine its focal length in cm. For which eye defe…