(a) | the distance between the objective and the eyepiece is \(20.02\) m. |
(b) | the magnification of the telescope is \(-1000\). |
(c) | the image of the planet is erect and diminished. |
(d) | the aperture of the eyepiece is smaller than that of the objective. |
1. | (a), (b), and (c) | 2. | (b), (c), and (d) |
3. | (c), (d), and (a) | 4. | (a), (b), and (d) |
A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:
1. | a large aperture contributes to the quality and visibility of the images. |
2. | a large area of the objective ensures better light-gathering power. |
3. | a large aperture provides a better resolution. |
4. | all of the above. |
An astronomical refracting telescope will have large angular magnification and high angular resolution when it has an objective lens of:
1. | small focal length and large diameter. |
2. | large focal length and small diameter. |
3. | large focal length and large diameter. |
4. | small focal length and small diameter. |
1. | \(46.0\) cm | 2. | \(50.0\) cm |
3. | \(54.0\) cm | 4. | \(37.3\) cm |
In an astronomical telescope in normal adjustment, a straight line of length \(L\) is drawn on the inside part of the objective lens. The eye-piece forms a real image of this line. The length of this image is \(l.\) The magnification of the telescope is:
1. \(\frac{L}{l}+1\)
2. \(\frac{L}{l}-1\)
3. \(\frac{L+1}{l-1}\)
4. \(\frac{L}{l}\)
The magnifying power of a telescope is \(9\). When it is adjusted for parallel rays the distance between the objective and eyepiece is \(20~\text{cm}\). The focal length of the lenses is:
1. \(10~\text{cm}, ~10~\text{cm}\)
2. \(15~\text{cm}, ~5~\text{cm}\)
3. \(18~\text{cm}, ~2~\text{cm}\)
4. \(11~\text{cm}, ~9~\text{cm}\)