JEE Main 2023PhysicsRay OpticsHardNumerical

JEE Main 2023Ray Optics Question with Solution

JEE Main 2023 (24 Jan Shift 1)

Question

As shown in the figure, a combination of a thin plano-concave lens and a thin plano-convex lens is used to image an object placed at infinity. The radius of curvature of both the lenses is 30 cm and refraction index of the material for both the lenses is 1.75. Both the lenses are placed at distance of 40 cm from each other. Due to the combination, the image of the object is formed at distance x= ______ cm, from concave lens.

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Show full solutionCorrect answer: 120
Correct answer
120

Step-by-step explanation

Using Lens Makers formula for the plano-concave part, we can write

1f1=(1.75-1)-130

  f1=-40 cm

Using Lens Makers formula for the plano-convex part, we can write

1f2=1.75-1130 f2=40 cm

Image from first lens will be virtual and on the left of first lens at focal length 40 cm. So the object for second lens will be 80 cm from second lens which is 2f2. Final image is formed at 80 cm from second lens on the right.
So, x=120.

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About this question

This is a previous-year question from JEE Main 2023, covering the Ray Optics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.