Question

A microscope is focused on an amoeba. Part A When a 0.15-mm-thick cover glass (n=1.50) is placed over the amoeba, by how far must the microscope objective be moved to bring the organism back into focus? Express your answer in millimeters. ΔsΔ s = nothing mm Request Answer Part B Must it be raised or lowered?

Answer 1

Answer:

$\Delta s=0.05\ mm$

∵The apparent depth is less therefore we need to raise the objective away from the placed object.

Explanation:

Given:

Real depth, $d_r=0.15\ mm$

refractive index of the medium, $n=1.5$

We know,

$n=\frac{d_r}{d_a}$

where:

$d_a=$ apparent depth of the object

$\therefore 1.5=\frac{0.15}{d_a}$

$d_a=0.1\ mm$

Now, the difference in the real and apparent depths:

$\Delta s=d_r-d_a$

$\Delta s=0.05\ mm$

∵The apparent depth is less therefore we need to raise the objective away from the placed object.