Q16. A compound microscope has fₒ = 1 cm and fₑ = 10 cm, with 20 cm lens separation. Its final image is at infinity. Magnitude of total angular magnification (D = 25 cm) equals:
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Question

Q16. A compound microscope has fₒ = 1 cm and fₑ = 10 cm, with 20 cm lens separation. Its final image is at infinity. Magnitude of total angular magnification (D = 25 cm) equals:

G1 Physics · Accepted Answer

GIVEN: fₒ = 1 cm, fₑ = 10 cm, L = 20 cm, D = 25 cm; final image at ∞. Step 1: Objective intermediate-image distance: vₒ = L − fₑ = 20 − 10 = 10 cm. Step 2: Exact objective magnification magnitude: |mₒ| = vₒ/fₒ − 1 = 10/1 − 1 = 9. Step 3: Eyepiece magnification for infinity: mₑ = D/fₑ = 25/10 = 2.5. Step 4: Total magnitude: |M| = 9 × 2.5 = 22.5. FINAL ANSWER: 22.5. Option B.