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.

Explanation

To solve the problem step by step, we will calculate the magnifying power of the compound microscope and the length of the tube.

### Step 1: Identify the given values
- Focal length of the objective lens (FO) = 4 cm
- Focal length of the eye lens (FE) = 10 cm
- Object distance from the objective lens (UO) = -6 cm (negative because the object is on the same side as the incoming light)
- Near point distance (D) = -25 cm (for a healthy eye)

...