A converging lens of focal length 5 cm is placed at a distance of 20 cm from a screen. How far from the lens should an object be placed so as to form its real image on the screen?

Explanation

To find the distance from the lens at which the object should be placed to form a real image on the screen, we can use the lens formula:

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

Where:
- \( v \) is the image distance from the lens,
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