Question

The magnifying power of a telescope is high if its objective and eyepiece have respectively

• A. large and small focal length.
• B. small focal lengths.
• C. large focal lengths.
• D. small and large focal length.

Hint:

To get a high magnifying power, use a telescope with a large objective focal length and a small eyepiece focal length.

Answer 1

The Correct Option is A

Step 1: Magnifying power of telescope.
The magnifying power of a telescope is given by the ratio of the focal length of the objective to the focal length of the eyepiece: \[ M = \frac{f_{\text{objective}}}{f_{\text{eyepiece}}} \] For maximum magnifying power, the objective should have a large focal length and the eyepiece should have a small focal length.
Step 2: Conclusion.
Thus, the correct answer is (A) large and small focal length.