Physics 2008 JAMB Past Questions - Question 37: An observer with normal eyes views an object with a magnifying glass of focal length 5cm. The angular magnification is

Correct Answer

D

Explanation

Angular magnification, M = - where D is least distance of distinct vision.therefore M = - (25/5 +1) = - 6
The angular magnification of a magnifying glass or any optical system can be calculated using the formula:

Angular Magnification (M) = 1 + (D / F)

Where:
- M is the angular magnification.
- D is the least distance of distinct vision, typically taken to be about 25 cm for a person with normal eyesight.
- F is the focal length of the magnifying glass.

In your case, you mentioned that the focal length of the magnifying glass is 5 cm. The least distance of distinct vision (D) is approximately 25 cm for a person with normal eyes.

Now, plug these values into the formula:

M = 1 + (25 cm / 5 cm)

M = 1 + 5

M = 6

So, the angular magnification when an observer with normal eyes uses a magnifying glass with a focal length of 5 cm is 6.