Advertisements
Advertisements
प्रश्न
State the condition under which a large magnification can be achieved in an astronomical telescope.
Advertisements
उत्तर १
Condition under which a large magnification can be achieved in an astronomical telescope:
In astronomical telescope, the light is incident from infinity on the objective lens and it forms image at the focus of the objective lens and for large magnification the length between the lens is so adjusted that the final image is formed at the least distance of the distinct vision from the eyepiece
Magnification of astronomical telescope is
\[(M . P )_\max = - \frac{f_o}{f_e}(1 + \frac{f_e}{d})\] To have large magnification power, \[f_o\] must be large as possible and \[f_e\] must be as small as possible.
उत्तर २
By increasing the focal length of objective lens and at the same time keeping the focal length of eye peice minimum we can increase the magnifying power of telescope
संबंधित प्रश्न
A small telescope has an objective lens of focal length 144 cm and an eyepiece of focal length 6.0 cm. What is the magnifying power of the telescope? What is the separation between the objective and the eyepiece?
Write two important advantages of reflecting telescope over a refracting telescope.
Write the two important factors considered to increase the magnifying power?
Draw a labelled ray diagram of an astronomical telescope to show the image formation of a distant object. Write the main considerations required in selecting the objective and eyepiece lenses in order to have large magnifying power and high resolution of the telescope.
An astronomical telescope is to be designed to have a magnifying power of 50 in normal adjustment. If the length of the tube is 102 cm, find the powers of the objective and the eyepiece.
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?
Draw a labelled ray diagram of an astronomical telescope in the near point adjustment position. A giant refracting telescope at an observatory has an objective lens of focal length 15 m and an eyepiece of focal length 1.0 cm. If this telescope is used to view the Moon, find the diameter of the image of the Moon formed by the objective lens. The diameter of the Moon is `3.48 xx 10^6`m, and the radius of the lunar orbit is `3.48 xx 10^8`m.
With the help of a ray diagram explain the working of a reflecting telescope.
Draw a labelled ray diagram showing the image formation by a refracting telescope. Define its magnifying power.
