An astronoical telescope consists of two thin lenses set 36 cm apart and has a magnifying power 8.Calculate the focal length of the lenses.

An astronomical telescope uses two lenses of power 10 D and 1 D.What is its magnifying power in normal adustment?

Two thin lenses of pwer +5D and -3D are in contact. What is the focal length of the combnation?

Two thin lenses of focal length f_1 and f_2 are placed in contant .The focal length of the composite lens will be

An astronomical telescope,when in normal adjustment has magnifying power 5.If the distance between two lenses is 24 cm,find the focal length of both the lenses.

Two thin lenses of focal lenths + 10 cm and - 5 cm are kept in contact.What is the focal length and

Two lenses f powers-1.5 and +2.75 D are kept in contact.Find the focal length of the combination.

The magnifying power of an astronomical telescope in the normal adjustment position is 20.If the length of the telescope is 105 cm in this adujustment ,find the focal lengths of the two lenses.

Two lenses of powers 10D - 5D are placed in contact Calculate the power of the new lens.

An astronomical telescope has an objective lens of focal length 20 m and eyepiece of focal lengh 1 cm. If this telescope is used to view the moon, find the diameter of the image formed by the objective lens given the diameter of the moon is 3.5 xx 10^6 m and radius of lunar orbit is 3.8 xx 10^8 m .