Question

The simple microscope having a lens of focal length 5 cm gives the magnification of (least distance of distinct vision \(= 25\) cm)

• A. 5
• B. 6
• C. 4
• D. 10
• E. 12

Hint:

For a simple microscope, magnification is higher when the image is at the near point (\(1 + D/f\)) than when at infinity (\(D/f\)).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
For a simple microscope (a single convex lens), the angular magnification (magnifying power) when the image is formed at the near point (D = 25 cm) is given by \(m = 1 + \frac{D}{f}\).

Step 2: Detailed Explanation:
Given: Focal length, \(f = 5 cm\). Least distance of distinct vision, \(D = 25 cm\). Magnification when the final image is at the near point: \[ m = 1 + \frac{D}{f} = 1 + \frac{25}{5} = 1 + 5 = 6 \] (If the image is at infinity, \(m = D/f = 5\). The question likely expects the near point magnification).

Step 3: Final Answer:
The magnification is 6.