Draw a labelled ray diagram to locate the image of an object formed by a convex lens of focal length $20 \, cm$ when the object is placed $30 \, cm$ away from the lens.

(N/A) Given: Focal length $f = +20 \, cm$,Object distance $u = -30 \, cm$.
Using the lens formula $\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$,we have:
$\frac{1}{v} = \frac{1}{f} + \frac{1}{u}$
$\frac{1}{v} = \frac{1}{20} + \frac{1}{-30} = \frac{3 - 2}{60} = \frac{1}{60}$
Therefore,$v = +60 \, cm$.
The image is formed at a distance of $60 \, cm$ on the other side of the lens. The ray diagram is as shown below.