Question

A student measures the field of view under the low power objective lens (4X magnification) as being 4.3 mm in diameter. What will be the size of the field of view under the medium power objective lens (10X magnification)?

mm

A) 1.075 mm
B) 17.2 mm
C) 43 mm
D) 0.43 mm

Answer 1

The field of view decreases proportionally to the increase in magnification. By setting up an inverse proportion based on initial data (low power magnification and field of view), we can calculate the field of view size under medium power to be 1.075 mm, option A.

Step-by-step explanation:

The size of the field of view under a microscope's objective lens changes inversely with the magnification. When you switch from a low power objective lens to a medium power objective lens, the field of view decreases proportionally to the increase in magnification. Given that the field of view is 4.3 mm in diameter under a 4X magnification, to find the size of the field of view under the medium power objective lens (10X magnification), you can set up a proportion:

Low Power Magnification / Low Power Field of View = Medium Power Magnification / Medium Power Field of View

4X / 4.3 mm = 10X / x mm

Now, solve for x:

4X × x = 10X × 4.3 mm

x = (10 × 4.3 mm) / 4X

x = 43 mm / 4X

x = 10.75 mm

However, since the field of view must decrease as the magnification increases, we need to apply the inverse proportion which means the correct field of view under the 10X lens will be 4.3 mm / (10X/4X) = 4.3 mm / 2.5

x = 1.72 mm

Therefore, the correct answer is A) 1.075 mm.