Geometric & Wave Optics
posted by Matrix School 1 .
An astronomical telescope consists an objective of focal lenght 100cm and an eyepiece of focal lenght 8cm.
calculate the angular magnification of the telescope and also determine the distance between the two lenses.

For astronomical telescopes, the objects are at infinity, so parallel rays reach the objective. The eyepiece is therefore placed at a distance from the objective equal to the focal length. At this location, the magnification is equal to the quotient of the focal lengths.
Magnification
= 100 cm / 8 cm
= 12.5 times.
Note: eyepieces usually have focal lengths in the millimetres range, so it is likely that the focal length of the eyepiece is 8 mm., in which case
Magnification
= 100 cm /8 mm
= 125 times. 
1. An object,30mm high ,is 90mm from a convex lens. The focal length is 60mm det the positive height an nature of the image. Draw an accurate diagram for the formation of the image. 2.calculate its magnification?
Respond to this Question
Similar Questions

Geo. & Wave Optics
An astronomical telescope consists an objective of focal lenght 100cm and an eyepiece of focal lenght 8cm. calculate the angular magnification of the telescope and also determine the distance between the two lenses. 
Physics
A telescope has a magnification of 20 and consists of two converging lenses, the objective and the eyepiece, fixed at either end of a tube 60.0 cm long. Assuming that this telescope would allow an observer to view a lunar crater in … 
physics
A laboratory (astronomical) telescope is used to view a scale that is 306 cm from the objective, which has a focal length of 20.0 cm; the eyepiece has a focal length of 2.40 cm. Calculate the angular magnification when the telescope … 
PHYSICS
An astronomical telescope has an objective lens of 80cm and an eyepiece of 5cm focal length.If the final image is formed 25cm from the eye piece when a distant object is viewed by the eye close to the eyepiece,determine the magnifying … 
physics
A telescope that has a 100 cm focal length objective and a 3.00 cm focal length eyepiece. Find the distance between the objective and eyepiece lenses in the telescope needed to produce a final image very far from the observer, where … 
physics
Galileo's first telescope used a convex objective lens with a focal length f = 1.65 m and a concave eyepiece. When this telescope is focused on an infinitely distant object, and produces an infinitely distant image, its angular magnification … 
Physics Help Please  Telescope
An astronomical refracting telescope is made from two lenses. the objective lens has a focal length of 114 cm, and the eyepiece lens has a focal length of 17 cm. a) What is the total length of the telescope? 
PHYSICS
The objective and eyepiece of an astronomical telescope are double convex lenses with refractive index 1.5. When the telescope is adjusted to infinity, the separation between the two lenses is 16 cm. If the space between the lenses … 
Physics
A Simple Astronomical Telescope In Normal Adjustment Has An Objective Of Focal Length 100cm And An Eye Piece Of Focal Length 5cm What Is The Angular Magnification 
Physics
A Simple Astronomical Telescope In Normal Adjustment Has An Objective Of Focal Length 100cm And An Eye Piece Of Focal Length 5cm What Is The Angular Magnification (a) 20 (b) 25 (c) 1/20 (d) 1/25