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Physics · PYQ NEET UG 2021
हिन्दीA point object is placed at a distance of \( 60 \text{ cm} \) from a convex lens of focal length \( 30 \text{ cm} \). If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of \( 40 \text{ cm} \) from it, the final image would be formed at a distance of:
Correct answer · Option 4
\( 20 \text{ cm} \) from the lens, it would be a real image.
Explanation
Lens forms image at \( v = +60 \text{ cm} \) behind it. The mirror is at \( 40 \text{ cm} \) from the lens, so the image acts as a virtual object for the mirror at \( 60 - 40 = 20 \text{ cm} \) in front of the mirror. The plane mirror forms a real image at \( 20 \text{ cm} \) in front of the mirror (which is \( 20 \text{ cm} \) from the lens).
