Answer:
= 1.9 cm
Explanation:
The magnification of a microscope is the product of the magnification of the eyepiece by the magnifier with the objective
M = M₀
Where M₀ is the magnification of the objective and is the magnification of the eyepiece.
The eyepiece is focused to the near vision point (d = 25 cm)
= 25 /
The objective is focused on the distances of the tube (L)
M₀ = -L / f₀
Substituting
M = - L/f₀ 25/
1) Let's look for the focal length of the eyepiece (faith)
= - L 25 / f₀ M
M = 400X = -400
= - 12 25 /0.40 (-400)
= 1.875 cm
Let's approximate two significant figures
= 1.9 cm