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 eye-piece 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: eye-pieces usually have focal lengths in the millimetres range, so it is likely that the focal length of the eye-piece 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?
To calculate the angular magnification of the telescope, we can use the formula:
Angular Magnification = (Angular Magnification of Objective) * (Angular Magnification of Eyepiece)
The formula for the angular magnification of a lens is:
Angular Magnification = (1 + (D / F))
Where:
D = Distance between the object and the lens
F = Focal length of the lens
First, let's calculate the angular magnification of the objective:
Angular Magnification of Objective = (1 + (D1 / F1))
Given that the focal length of the objective (F1) is 100 cm, and the distance between the objective and the object is not provided, we cannot directly calculate the angular magnification of the objective.
Now, let's calculate the angular magnification of the eyepiece:
Angular Magnification of Eyepiece = (1 + (D2 / F2))
Given that the focal length of the eyepiece (F2) is 8 cm, and the distance between the eyepiece and the image formed is also not provided, we cannot directly calculate the angular magnification of the eyepiece.
To determine the distance between the two lenses, we need additional information about the telescope, such as the distance between the objective and the eyepiece. Without this information, it is not possible to determine the distance between the two lenses.
In summary, without the distances between the object and the objective, and the image and the eyepiece, we cannot calculate the angular magnification of the telescope or determine the distance between the two lenses.