Advertisements
Advertisements
Question
Define the term ‘resolving power of a telescope’.
Advertisements
Solution 1
The resolving power of an astronomical telescope is defined as the reciprocal of the smallest angular separation between two point objects whose images can just be resolved by the telescope.
R.P = `(1.22 lambda)/D`
Solution 2
Resolving power is the ability of the telescope to distinguish clearly between two points whose angular separation is less than the smallest angle that the observer’s eye can resolve.
RELATED QUESTIONS
Draw a schematic ray diagram of a reflecting telescope showing how rays coming from a distant object are received at the eyepiece.
- For the telescope is in normal adjustment (i.e., when the final image is at infinity)? what is the separation between the objective lens and the eyepiece?
- If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens?
- What is the height of the final image of the tower if it is formed at 25 cm?
You are given the following three lenses. Which two lenses will you use as an eyepiece and as an objective to construct an astronomical telescope ? Give reason
| Lenses | Power (D) | Aperture (cm) |
| L1 | 3 | 8 |
| L2 | 6 | 1 |
| L3 | 10 | 1 |
How is the working of a telescope different from that of a microscope?
The eyepiece of an astronomical telescope has a focal length of 10 cm. The telescope is focussed for normal vision of distant objects when the tube length is 1.0. m. Find the focal length of the objective and the magnifying power of the telescope.
A lady cannot see objects closer than 40 cm from the left eye and closer than 100 cm from the right eye. While on a mountaineering trip, she is lost from her team. She tries to make an astronomical telescope from her reading glasses to look for her teammates. (a) Which glass should she use as the eyepiece? (b) What magnification can she get with relaxed eye?
Which type of telescope uses a convex lens as the eyepiece, since there is no necessity for an erect image?
In an astronomical (refracting) telescope, the objective lens has:
During the formation of an image in a telescope under normal adjustment, the eyepiece is adjusted so that the intermediate image lies:
According to Rayleigh's criterion for the angular separation between two resolvable objects, the correct relation is:
