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A diverging lens with magnitude of focal length 25 cm is placed at a distance of 15 cm from a converging lens of magnitude of focal length 20 cm. A beam of parallel light falls on the diverging lens. The final image formed is

Asked in JEE Main 2017 · Combinations and silvered lenses

• (1) real and at a distance of 40 cm from convergent lens.
• (2) virtual and at a distance of 40 cm from convergent lens.
• (3) real and at a distance of 40 cm from the divergent lens.
• (4) real and at a distance of 6 cm from the convergent lens.

Step-by-step solution

Why the other options are wrong

• (2) Gets the distance right but misreads the positive v as a virtual image.
• (3) Measures the final image distance from the wrong lens.
• (4) Treats the virtual image of the diverging lens as lying on the far side of the converging lens, giving a wrong object distance.

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