# Building a microscope with two different power lenses

## Homework Statement

You've been asked to build a 14X microscope from a 2X magnifying lens and a 5X magnifying lens.
What will be the tube length of your microscope?

Meye = 25/feye
Mobj = -L/fobj
M = (Meye)(Mobj)

## The Attempt at a Solution

First, are you supposed to use the 5X as the objective? That's what I assumed since it's a higher power, but I'm not sure why exactly?

Then I'm not quite sure what to do next. I found the feye value to be 12.5 cm. But I get don't know what to do after that. If someone could just point me in the right direction I'd appreciate it! Thanks!

## Answers and Replies

Related Introductory Physics Homework Help News on Phys.org
Simon Bridge
Homework Helper

## Homework Statement

You've been asked to build a 14X microscope from a 2X magnifying lens and a 5X magnifying lens.
What will be the tube length of your microscope?

Meye = 25/feye
Mobj = -L/fobj
M = (Meye)(Mobj)

## The Attempt at a Solution

First, are you supposed to use the 5X as the objective? That's what I assumed since it's a higher power, but I'm not sure why exactly?
What difference does it make?
Then I'm not quite sure what to do next. I found the feye value to be 12.5 cm. But I get don't know what to do after that. If someone could just point me in the right direction I'd appreciate it! Thanks!
Well you need to line up the lenses involved and work out what the magnification is for different 5x-2x separations. Do you know how to work out the combined magnification of two lenses?