Match List - I with List - II.
| List - I | List - II |
| (A) Simple microscope | (I) A concave mirror is used as an objective |
| (B) Compound microscope | (II) Two convex lenses both of small focal length |
| (C) Refracting Telescope | (III) Two convex lenses, one of small focal length other of large focal length |
| (D) Reflecting Telescope | (IV) Single convex lens of small focal length |
Choose the correct answer from the options given below :
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A)-(IV), (B)-(II), (C)-(III), (D)-(I)
Each instrument is identified by its objective and eyepiece: short focal lengths magnify a near object, while a telescope needs an objective of large focal length.
(A) Simple microscope — this matches (IV) Single convex lens of small focal length. A simple microscope (magnifying glass) is one converging lens, and its magnifying power \( 1 + D/f \) is large only when \( f \) is small.
(B) Compound microscope — this matches (II) Two convex lenses both of small focal length. The objective forms a magnified real image of the near object and the eyepiece magnifies it again; both lenses have short focal lengths so that each stage magnifies strongly.
(C) Refracting Telescope — this matches (III) Two convex lenses, one of small focal length other of large focal length. Its magnifying power is \( f_o/f_e \), so it uses an objective of large focal length and an eyepiece of small focal length.
(D) Reflecting Telescope — this matches (I) A concave mirror is used as an objective. A large concave mirror collects the light, which avoids chromatic aberration and the difficulty of making and supporting very large lenses.
NCERT (2026-27):
The Microscope – “A simple magnifier or microscope is a converging lens of small focal length ….”
The Microscope – “… For much larger magnifications, one uses two lenses, one compounding the effect of the other. This is known as a compound microscope.”
The Microscope – “… Clearly, to achieve a large magnification of a small object (hence the name microscope), the objective and eyepiece should have small focal lengths.”
Telescope – “… It also has an objective and an eyepiece. But here, the objective has a large focal length and a much larger aperture than the eyepiece.”
Telescope – “… For these reasons, modern telescopes use a concave mirror rather than a lens for the objective. Telescopes with mirror objectives are called reflecting telescopes.”