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MICRO-STRUCTURE ANALYSIS OF PLANT TISSUES - Lublin

MICRO-STRUCTURE ANALYSIS OF PLANT TISSUES - Lublin

MICRO-STRUCTURE ANALYSIS OF PLANT TISSUES - Lublin

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In turn, the image distance y 1 is approximately equal to the tube length l<br />

y 1 ≈ l (3)<br />

Therefore, the objective magnification ratio p ob , in accordance with (2) and<br />

(3), equals:<br />

p ob<br />

1<br />

The true image A 1 B 1 , generated by the objective, is formed close to the focus,<br />

between the eyepiece focus and the eyepiece, so its distance from the eyepiece<br />

may be accepted as equal to the focal length of the eyepiece f 2 , i.e.:<br />

(4)<br />

x 2 ≈ f 2 (5)<br />

Distance y 2 of the virtual image A 2 B 2 is approximately equal to d, then:<br />

y 2 ≈ d (6)<br />

where d – distance of image A 2 B 2 from the eye of the observer (so-called<br />

“good vision” distance)<br />

Therefore, the eyepiece magnification ratio can be expressed with<br />

the formula:<br />

p ok<br />

y1<br />

=<br />

x<br />

≈<br />

y<br />

=<br />

x<br />

And thus, in accordance with (1), (4) and (7) the total magnification ratio<br />

of the microscope, p, can be expressed with the formula:<br />

p =<br />

To obtain very high magnification ratios, microscopes are built with<br />

objectives and eyepieces having very short focal lengths. In such cases,<br />

the objectives and eyepieces are not single lenses but systems of several lenses [3,<br />

4, 5, 6, 7, 8].<br />

2<br />

2<br />

l<br />

f<br />

d<br />

1<br />

≈<br />

l<br />

f 1<br />

f 2<br />

d<br />

f<br />

2<br />

(7)<br />

(8)<br />

22

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