The lens of our eye has a diameter of 0.8 cm .How much fainter star can be seen through the 508 cm objective telescope at Mount Polomar in U.S.A?

The objective of telescope A has a diameter 3 times that of the objective of telescope B.How much greater amount of light is gathered by A as compared to B?

A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. what is the separation between the objective lens and the eyepiece?

A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. (A) what is the separation between the objective lens and the eyepiece? (B) 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?

A telescope has objective lens of focal length 15m. If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens? The diameter of the moon is 3.48 xx 10^6m , and the radius of lunar orbit is 3.8 xx 10^8m .

A certain nearsighted person cannot see objects clearly,when they are more than 78 cm from either eye. The person's near pint is 23 cm.How is this affected,when viewing through the corrective lenses?Assume that the lenses in spectales are 3 cm in front of the eye.

In Fig., you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade. Assume pi = 22/7

A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects.The can be resolved by the telescope, when the mean wavelength of light is 5,000 overset @A ,is of the order of