2.1.3 measuring objects seen with a light microscope

Question 1

define an eyepiece graticule

Answer 1

measuring device placed in the eyepiece of a microscope & acts as a ruler when you view an object under it

Question 2

define a stage graticule

Answer 2

precise measuring device with small scale that is placed on microscope stage & used to calibrate value of eyepiece graticule divisions at different magnifications

Question 3

describe the steps of using a stage graticule to calibrate the eyepiece graticule

Answer 3

1. insert eyepiece graticule into x10 eyepiece of microscope
2. place stage graticule on microscope stage & bring into focus using low power (x4) objective - total magnification = x40
3. align eyepiece graticule with stage graticule & check value of 1 eyepiece division at this magnification
4. now use x10 objective lens & focus stage graticule
5. align them

Question 4

how many divisions does the eyepiece graticule have

Answer 4

100

Question 5

how long is the stage graticule & how many divisions

Answer 5

• 1mm long
• 100 divisions (each division is 0.01mm or 10 micrometers)