Select the correct option

Options

A. The aperture and focal length of the objective lens of microscope is smaller than eye-piece lens
B. The aperture and focal length of the objective lens of telescope is large than eye-piece lens
C. The magnifying powers of astronomical telescope and terrestrial telescope are same
D. All of these

Answer

To solve the question, we need to analyze each option provided and determine which one is correct regarding the properties of lenses in microscopes and telescopes.

### Step-by-Step Solution:

1. **Understanding the Terms:**
- **Aperture:** The aperture of a lens is the opening through which light enters. A larger aperture allows more light to enter, which is important for clarity and brightness in optical devices.
- **Focal Length:** The focal length of a lens is the distance from the lens to the point where it focuses light. A shorter focal length indicates a stronger lens that can converge light more sharply.

2. **Analyzing Option 1:**
- The statement claims that the aperture and focal length of the objective lens of a microscope are smaller than that of the eyepiece.
- In a microscope, the objective lens indeed has a smaller aperture and focal length compared to the eyepiece. This is because the objective lens is designed to focus closely on the specimen, while the eyepiece magnifies the image produced by the objective lens.
- **Conclusion:** Option 1 is correct.

3. **Analyzing Option 2:**
- This option states that the aperture and focal length of the objective lens of a telescope are larger than those of the eyepiece lens.
- In telescopes, the objective lens (or mirror) is designed to gather light from distant objects and thus has a larger aperture and longer focal length compared to the eyepiece lens, which is used for magnification.
- **Conclusion:** Option 2 is also correct.

4. **Analyzing Option 3:**
- The statement claims that the magnifying power of astronomical telescopes and terrestrial telescopes are the same.
- While both types of telescopes can have similar magnifying powers, they are designed for different purposes. Astronomical telescopes are optimized for viewing celestial objects, while terrestrial telescopes are designed for viewing objects on Earth. Their magnifying powers can differ based on design and intended use.
- **Conclusion:** Option 3 is not necessarily correct.

5. **Final Conclusion:**
- Since options 1 and 2 are correct, but option 3 is not, we cannot select option 4 (which states all options are correct).
- Therefore, the correct options are 1 and 2, but not 3 or 4.