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A compound microscope uses an objective lens of focal length `4 cm` and eye lens of focal length `10 cm`. An object is placed at `6 cm` from the objective lens. Calculate magnifying power of compound microscope if final image is formed at the near point. Also, calculate length of the tube of compound microscope. |
Answer» Correct Answer - `7` ; `22 cm` Here, `f_(0) = 4 cm, f_(e) = 10 cm, u_(0) = - 6 cm` From `(1)/(v_(0)) - (1)/(u_(0)) = (1)/(f_(0))` `(1)/(v_(0)) = (1)/(f_(0)) + (1)/(u_(0)) = (1)/(4) - (1)/(6) = (1)/(12)` `v_(0) = 12 cm` `M = (v_(0))/(|u_(0)|)(1 + (d)/(f_(e))) = (12)/(6)(1 + (25)/(10)) = 7` Length of microscope `= L = v_(0) + f_(e)` `= 12 + 10 = 22 cm` |
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