"MICRON" µ -or- "MICROMETER" µm
--- basic unit used in measuring microscopic objects
--- conversion: 1mm = 1,000µ

"FIELD OF VISION"
--- microscopic field in which specimens are seen

"LINEAR MAGNIFICATION"
--- aligning of objective lens with ocular piece

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Diameter Method
--- measure diamter of field of vision
--- use ruler

~ the LPO's field of vision (FOV) is usually 1.1mm to 1.5mm in diameter ~

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Computation Method
--- aim: get FOV of HPO
--- given:

• FOV(LPO) in µ
• ratio of magnification (ROM) of objectives given: ROM = LPO/HPO

example:

given
FOV(LPO) = 1.1mm -convert to- 1,100µ
LPO 10x magnification; HPO 50x magnification

equation
ROM = LPO/HPO
ROM x FOV(LPO) = (FOV)(HPO)

solution
ROM = 10/50 = 1/5
1/5 x 1,100 = 220

final answer
field of vision of HPO is 220µ.