# Optical Instrument Formulas

Applications of Optical Instruments are wide and it is necessary to be aware of the concept. In order to help you understand the concept better, we have listed all the Important Optical Instrument Formulas under one roof. The Cheat Sheet of Optical Instrument covers various formulae for Simple Microscope, Compound Microscope, Telescope, etc. We have everything covered in our formulae list right from basic to advanced level. For more help, you can always look up to Physics Formulas and grasp the concepts easily.

## Optical Instrument Formulae List

1. Simple microscope

(a) Image is at infinity (for point)
M.P. = $$\frac{D}{u}=\frac{D}{f}$$
M.P. → Magnifying power
D → Least distance of distinct vision

(b) Image is at D
M.P. = 1 + $$\frac{D}{f}$$

2. Compound microscope

(a) Final image at ∞
M.P. = –$$\frac{v}{u}\left[\frac{D}{f_{e}}\right]$$
L = u + fe = Length of tube

(b) Final image is at D
M.P. = –$$\frac{v}{u}\left[1+\frac{D}{f_{e}}\right]$$
|M.P.| ≅ $$\frac{L}{f_{0}} \times\left[1+\frac{D}{f_{e}}\right]$$

3. Telescope

(a) Final image at ∞
M.P. = – $$\frac{f_{o}}{f_{e}}$$
L = fo + fe

(b) Final image is at D
M.P. = – $$\frac{f_{o}}{f_{e}}\left(1+\frac{f_{e}}{D}\right)$$;
L = fo + $$\frac{f_{e}}{f_{e}+D}$$

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