An insect 1.3 mm tall is placed 0.9 mm beyond the focal point of the objective l

Question

An insect 1.3 mm tall is placed 0.9 mm beyond the focal point of the objective lens of a compound microscope. The objective lens has a focal length of 14 mm , the eyepiece a focal length of 30 mm .

A)Where is the image formed by the objective lens? Give your answer as the distance from the image to the lens. Express your answer using two significant figures (___mm)

B)How tall is the image mentioned in part A? Express your answer using two significant figures. (__mm)

C)If you want to place the eyepiece so that the image it produces is at infinity, how far should this lens be from the image produced by the objective lens?Express your answer using two significant figures. (__mm)

D)Under the conditions of part C, find the overall magnification of the microscope. Express your answer using two significant figures. (__mm)

Explanation / Answer

1/v - 1/u = 1/f
a) u = -14.9 mm
f = 14 mm
v = 231.777 mm
b) m = -v/u = h'/h
231.777/14.9 = h'/1.3
h' = 20.222 mm
c) u = ?
v = infinity
so, f = -u
u = -30 mm
do distance of ewyepiece from objective = 231.777 - 30 = 201.777 mm
d) overall magnification = 201.777/14 = 14.41264

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.