question_answer

An object is placed at a distance of 15 cm from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.

Answer:

Given, \[u=-15\,cm,\,f=20\,cm\]

\[\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\]

\[\frac{1}{20}=\frac{1}{v}+\frac{1}{15}\]

\[\frac{1}{v}=\frac{1}{20}-\frac{1}{15}\]

\[v=-60\,cm\]

Four characteristics of the image formed by the lens are:

(i) Virtual, (ii) Erect, (iii) At a distance of 60 cm on the same side of the lens as the object, (iv) Enlarged image.