A compound microscope consists of an objective lens of focal length \(2.0~\text{cm}\) and an eyepiece of focal length \(6.25~\text{cm}\) separated by a distance of \(15~\text{cm}.\) How far from the objective should an object be placed in order to obtain the final image at the least distance of distinct vision \((25~\text{cm})?\)
1. \(2.5~\text{cm}\)
2. \(0.5~\text{cm}\)
3. \(1.5~\text{cm}\)
4. \(5.0~\text{cm}\)
A person with a normal near point \((25~\text{cm})\) using a compound microscope with an objective of focal length \(8.0~\text{mm}\) and an eyepiece of focal length \(2.5~\text{cm}\) can bring an object placed at \(9.0~\text{mm}\) from the objective in sharp focus. What is the separation between the two lenses?
1. \(7.20~\text{cm}\)
2. \(9.47~\text{cm}\)
3. \(2.50~\text{cm}\)
4. \(2.27~\text{cm}\)
A man with a normal near point \(25~\text{cm}\) reads a book with a small print using a magnifying glass: a thin convex lens of focal length \(5~\text{cm}.\) What is the ratio of maximum and the minimum angular magnification (magnifying power) possible using the above simple microscope?
| 1. | \(\dfrac65\) | 2. | \(\dfrac56\) |
| 3. | \(\dfrac32\) | 4. | \(\dfrac23\) |
The linear magnification and angular magnification in the microscope have similar magnitude when the image is at a distance of:
1. \(35~\text{cm}\)
2. \(\infty\)
3. \(25~\text{cm}\)
4. none of these