Match List-I with List-II :
| List-I | List-II | ||
| Optical Instrument | Nature of Lens/mirror used | ||
| (A) | Human eye | (I) | Concave mirror of large aperture and large focal length |
| (B) | Microscope | (II) | Objective lens of large aperture and large focal length |
| (C) | Reflecting telescope | (III) | Lens of adjustable focal length |
| (D) | Refracting telescope | (IV) | Objective of small aperture and small focal length |
Choose the correct answer from the options given below :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
A microscope magnifies a nearby tiny object, so its objective has a short focal length; a telescope collects light from distant objects, so its objective (lens or mirror) has a large aperture and long focal length.
(A) Human eye — this matches (III) Lens of adjustable focal length. The ciliary muscles change the curvature of the eye lens, so its focal length changes (accommodation) to focus near and far objects.
(B) Microscope — this matches (IV) Objective of small aperture and small focal length. A short focal length objective forms a large real image of an object placed just beyond its focus.
(C) Reflecting telescope — this matches (I) Concave mirror of large aperture and large focal length. Its objective is a concave mirror; a large aperture gathers more light and gives better resolution.
(D) Refracting telescope — this matches (II) Objective lens of large aperture and large focal length. Its magnifying power is \( f_o/f_e \), so the objective lens has a long focal length.